What is a necessity and what isn't a necessity is very largely subject to interpretation. For almost seven years, I took the subway in from the Maryland suburbs and worked in downtown Washington, DC. I wore a suit and tie to work, so I had clothing and fry-cleaning expenses that were not reimbursed. Nine times out of ten, I got to work early and grabbed coffee and a muffin and sat for a few minutes and BS'd with the restaurant's manager, who taught me a lot about sales and occasionally comped me. I often would have lunch and/or coffee with a client during the day--we each paid for our own and that was non reimbursed. I had to take a cab to a meeting every so often. I moved to a building with an office that had coffee service and often had breakfast out for its staff (or had a breakfast meeting where they would intentionally over-order for that reason), so those expenses disappeared. I also lost the client I'd gone to lunch with often, but for nothing other than the sake of convenience and getting away from my desk and off the phone all day, I'd have lunch at a coffee shop down the street.

You may or may not find parallels with my old routine at my first professional job out of college and that of an experienced farmer in the Midwest (I now live in Missouri--I'm a Midwesterner, but I'm not a farmer), or with those of the CEO of a large corporation. My necessities and the farmer's necessities, and those of the CEO are completely different.

And it can change in the blink of an eye. Since 2005, my necessities have dramatically changed.. I left my well-paying job in retail sales and merchandise purchasing (including overseas travel) after the first of what would be 4 strokes and neurosurgery 7 times (to date). I even had a stroke on vacation while recovering in between surgeries.

There are so many variables that pinning down an amount is difficult. One CAN live without internet, or at least without paying for it. Try it for one day--use it only at the office, a public library or other public place. I'm a consultant now who's currently writing a book but I don't use the internet--or even text messaging.from my cell phone. And it's not like I don't understand the technology--I'm in my 30s. My entire office is virtual--I can (and often need to, wherever I am) sit down at any computer with an internet connection and within a few minutes, my email, my voice-mail (from four different phone numbers) and my faxes (out from one number and in from two or three numbers), plus an entire virtual switchboard--plus an upcoming website I'm designing and access to any file I'd need remotely, are on screen. And I don't use one of those virtual office services--it's just a few log-ins and I'm done. I can run the whole thing from anywhere. It can be done.

Similarly, how much a child spends swings widely. You haven't defined child, so I'll use the legal definition--under age 18. A sixteen-year-old with a drivers' license and a girlfriend is going to spend far more out of his pocket than my first-grader son will. (And that, by the way, is an additional spending necessity for the average male, if he has kids--but how many? Public school or private school? etc, etc.)

I'd think it's impossible to give a concrete number, or even a range for the answers to either question.

This question largely depends on what you define as "necessity." Here's what I'm getting at: You have co-workers and fostering a sense of camaraderie is important for your career, so going out with them for a beer after work once a month or so is a necessity. Or, you have a close group of friends from college who are up and coming, or already well established and important to you personally (long time friends) and also professionally, and you have a once a month poker night that costs $20 bucks to ante up and another $10 to kick in for food and drinks. Is this a necessity? Most people would recognize yes. You might be in a financial bracket where country club membership is an absolute necessity for your profession (ex lawyer). Also, since your question referred to the word “average” I’ll assume you’re not a hardcore hoard-every-penny-person, and therefore will contribute to a collection at work for someone’s baby-shower or take your Mom out to dinner on her birthday, etc.

So, here's a detailed breakdown going from "average minimal" ($34k/yr) to upper middle class with lots of obligations ($250k/yr). You can decide where your life-style falls. *d items may or may not apply at certain income levels. (I don't know how to put a table into Mahalo so the numbers next to each item are low income budget first, high income budget next.)

Yearly Earnings = $34,000 / $250,000
Monthly Cost (Budget)

Housing = $600 / $3,000
Utilities (sewer/water) = $30 / $30
Utilities (heat-a/c) = $100 / $400
Cable/phone/internet bundle = $150 / $150
Cell phone (assume yes, like internet) = $60 / $150
Electronics acquisition/repair = $30 / $150
Transportation (gas or bus fare) = $100 / $200
Car pmt & maintenance = -- / $600
Household furnishings and utensils = $50 / $1,000
Cleaning supplies = $15 / $60
Household maintenance = -- / $800
Food = $450 / $800
Toiletries = $20 / $50
Clothing-personal = $50 / $200
Clothing-work (uniforms) = $30 / --
Laundry/Dry Cleaning = $20 / $150
Hair cuts = $15 / $35
Medical/Dental/Vision out-of-pocket = $10 / $50
Insurances
*Renters/Homeowners = -- / $120
*Auto = -- / $300
*Health = $300 / $900
*Life = -- / $150
Emergency Fund = -- / $500
*Retirement Fund = -- / $800
Bank fees (checking/investment) = $20 / $20
*Property taxes (home-car-possibly other) = -- / $450
Payroll taxes = $400 / $3,125
*Dues (union, professional) = $20 / $40
*Membership(s) = -- / $200
Entertainment/Gifts (mom, girlfriend) = $40 / $300
Dining Out = $100 / $800
*Student Loans = $150 / $1,000
*Travel/Vacation = -- / $400
*Pet food/care = -- / $130
Donations/church = $30 / $200
Monthly Total = $2,770 / $17,260

Daily cost (rounded) = $92 / $575

Teens and children are going to cost approximately the same because when you transition off disposable diapers and child care, you transition into extra-curricular activities like sports, music, proms and electronics.

$34,000 / $250,000
Monthly Cost
(These are add’l per child to the basic living expenses above, unless otherwise noted.)

Housing = $600 / (Covered above)
Utilities (sewer/water) = $30 / $30
Utilities (heat-a/c) = $100 / (Covered above)
Cable/phone/internet bundle = (Covered above) / (Covered above)
Cell phone (assume yes, like internet) = $20 / $100
Electronics acquisition/repair = $30 / $200
Transportation (gas or bus fare) = $100 / $100
Household furnishings and utensils = $50 / (Covered above)
Cleaning supplies = $15 / (Covered above)
Household maintenance = -- / (Covered above)
Food = $450 / $600
Toiletries = $20 / $50
Clothing-personal = $50 / $150
Laundry/Dry Cleaning = $20 / $20
Hair cuts = $15 / $35
Medical/Dental/Vision out-of-pocket = $10 / $50
Insurances
*Health = $300 / $500
*Life = -- / $50
*Membership(s) = -- / $50
Entertainment/Gifts (mom, etc ) = $20 / $200
Dining Out = $20 / $200
*Student Loans or college fund = -- / $400
Childcare/Extracurricular = $500 / $500
*Travel/Vacation = -- / $200
*Pet food/care = -- / (Covered above)
Donations/church = $30 / (Covered above)
Monthly Total = $2,360 / $3,335

Daily cost (rounded) = $78** / $110

**oops…you’re screwed unless your wife works too.

One observation about the above:
Three items in particular are especially out of whack relative to income and they are housing cost (rent/mortgage and property taxes), insurances and payroll taxes. In my personal opinion, all levels of governments have to get smaller thereby reducing payroll and property taxes (yes, much fewer government/state sponsored public services!), and real estate values must come significantly down (still!). Once average housing equals a monthly (principle-interest-taxes) payment that equals 25% of the average income of ONE worker per household the middle class will be able to restore itself to a 1960s quality of life. Insurances should be done away with entirely or be based on deductibles of $50,000, so they are catastrophic only and therefore MUCH LESS expensive and have MUCH LESS impact on service provider costs. (Sorry for the segue, just couldn’t resist once the actual present daily male cost of living was outlined above.)

I think you are going to run into an issue depending on where the answerer is from. Depending on the cost of living for the area, some people will spend more or less on the same products and services.

I'm not sure about the teenager or child, but I have broken down my budget for last month for you. My income is very close to the median income in my area, so I figure my daily expenses should be pretty average.

Taking into account only "necessities" and assuming I consume exactly the same amount as my wife and all monthly expenses were split 50/50, here were my daily expenses for April 2010:

Rent - $19.63
Groceries/Food - $5.40
Utilities - $2.65
Telecommunications - $2.73
Gasoline - $1.79
Healthcare/Medical - $4.63

I didn't include cable, entertainment, etc. as they are not considered necessity.

If human means human of any race or country, the numbers mentioned so far are too high. More than half of the world population probably live on less than $2 a day. More than one billion people live on less than $1 a day. If you look at world income distribution patterns, you will get shocked. I think the average human male adult spends not more than $10 a day. $8 is my estimate for teenage males and $6 for male children. Anyone that has lived or backpacked in overpopulous countries will probably think my estimates are too high. Money is not spread out flat in global society. There are too many poor people in the world.

Well there is a great article on the topic here.

This is where I found out that the median income of the US is 46,000. Dual income fairs better at $67,348

http://www.mybudget360.com/how-much-does-the-average-american-make-breaking-down-the-us-household-income-numbers/

A Budget based on that income, that does include income gives a total expence of 2,768 so we are looking at +$128 at the end of the month. Let's strip this down to basic needs by removing the $100 for Movies Gym and Dinner as well as 50 for camping trips.

So we are looking at $2,618 a month as an average for needs.
http://www.mybudget360.com/the-perfect-46000-budget-learning-to-live-in-california-for-under-50000/

Calculating for teenagers who may or may not have jobs and children gets more complex, so I research based on how much it costs to raise a male child as it is the parent footing the living expences.

Well we are looking at $291,570 to raise a child from 0-17 or roughly 24,298 a year.
http://www.efinancialblog.com/insurance-qa-cost-raise-child/

I found a calculator and it calculated 0-12 years old being 15,308 a year.
A teen from 13-18 calculated for the same cost 15,308 a year.
http://www.thehealthybelly.com/baby_cost_calculator.php

The above did not separate male from female children & what I found discussing which gender cost more was largely opinion based.
http://www.collegenet.com/elect/app/app?service=external/Forum&sp=2965