RE: Ryan Sheckler Clothing online:
His official website is here http://www.ryansheckler.com/
couldn't check if it also has his merch as it did not load for me.

This Ryan Sheckler Clothing page http://www.mahalo.com/ryan-sheckler-clothing
has many links for where to buy his clothing.

Below are some pages from amazon.com under the word Sheckler.
Got a bit carried away but found them very interesting.
You can check yourself if they are official gear or not etc.

etnies Little Kid/Big Kid Sheckler 3 Sneaker
http://www.amazon.com/etnies-Little-Sheckler-Sneaker-Toddler/dp/B001D6MSNM/
http://ecx.images-amazon.com/images/I/41x75GVrX8L._AA280_.jpg

Etnies Little Kid/Big Kid Kids Sheckler Sneaker
http://www.amazon.com/Etnies-Little-Sheckler-Sneaker-Toddler/dp/B001UQ6R1Y/
http://ecx.images-amazon.com/images/I/41SX4etxJ7L._AA280_.jpg

etnies Men's Sheckler 2 Sneaker
http://www.amazon.com/Etnies-Mens-Sheckler-Sneaker-Olive/dp/B0017GMQWG/
http://ecx.images-amazon.com/images/I/418V8E4Hr3L._AA280_.jpg

etnies Men's Sheckler 2 Sneaker
http://www.amazon.com/etnies-Sheckler-Sneaker-Black-Royal/dp/B001RCV7NE/
http://ecx.images-amazon.com/images/I/41r8cIMEseL._AA280_.jpg

etnies Men's Sheckler Sneaker
http://www.amazon.com/etnies-Sheckler-Sneaker-White-Black/dp/B001BXZ8KC/
http://ecx.images-amazon.com/images/I/41ttvq3aBZL._AA280_.jpg

etnies Men's Sheckler 2 Skate
http://www.amazon.com/etnies-Mens-Sheckler-Skate-Black/dp/B002BDV03K/
http://ecx.images-amazon.com/images/I/41oEc5oexbL._AA280_.jpg

etnies Men's etnies SHECKLER 2 SKATE SHOES
http://www.amazon.com/etnies-Mens-SHECKLER-SKATE-SHOES/dp/B001UHY6IE/
http://ecx.images-amazon.com/images/I/41Sf0W8lJ7L._AA280_.jpg

ETNIES Sheckler 2 New Skate Black Mens
http://www.amazon.com/ETNIES-Sheckler-Skate-Black-Mens/dp/B001L4CJFI/
http://ecx.images-amazon.com/images/I/51QHwQB8DdL._AA280_.jpg

etnies Men's etnies SHECKLER 2 SKATE SHOES
http://www.amazon.com/etnies-Mens-SHECKLER-SKATE-SHOES/dp/B002U053ZA/
http://ecx.images-amazon.com/images/I/41Ad8k6QuTL._AA280_.jpg

etnies Men's Sheckler Sneaker
http://www.amazon.com/Etnies-etnies-Mens-Sheckler-Sneaker/dp/B0017GMS7O/
http://ecx.images-amazon.com/images/I/41ttvq3aBZL._AA280_.jpg

etnies Men's Sheckler 2 Sneaker
http://www.amazon.com/etnies-Mens-Sheckler-2-Sneaker/dp/B001KYEPT2/
http://ecx.images-amazon.com/images/I/41r8cIMEseL._AA280_.jpg

Bones Wheels "Sheckler" Tshirt - S
http://www.amazon.com/Bones-Wheels-Sheckler-Tshirt-S/dp/B0016A23G2/
http://ecx.images-amazon.com/images/I/41C0KdLq4DL._SL500_AA280_.jpg

Volcom Sheckler Denim Pant - Men's
http://www.amazon.com/Volcom-Sheckler-Denim-Pant-Mens/dp/B001O595F6/
http://ecx.images-amazon.com/images/I/31k2C-rLuDL._AA280_.jpg

Oakley Sideways Ryan Sheckler Signature Series (Special Edition) Sunglasses
http://www.amazon.com/Oakley-Sideways-Sheckler-Signature-Sunglasses/dp/B002YVBC8M/
http://ecx.images-amazon.com/images/I/319NyIcQ2uL._AA280_.jpg

Oakley Men's Sideways Ryan Sheckler Asian Fit Sunglasses
http://www.amazon.com/Oakley-Sideways-Sheckler-Asian-Sunglasses/dp/B002EAZ7U2/
http://ecx.images-amazon.com/images/I/3114Lil9KUL._AA280_.jpg

Oakley Men's Sideways Sheckler Sunglasses
http://www.amazon.com/Oakley-Mens-Sideways-Sheckler-Sunglasses/dp/B002EL2YJS/
http://ecx.images-amazon.com/images/I/31NWWsj2uwL._AA280_.jpg

You can buy Ryan Sheckler clothing at JC Penney:
http://www3.jcpenney.com/jcp/default.aspx

For clothing that you can't find at JC Penney (like the sweatshirt below), you should try searching Sheckler in Google's product search (http://www.google.com/prdhp?hl=en&tab=wf). You'll get a lot of results for hoodies and shoes being sold by skate stores that you might have a hard time locating otherwise. Plus, you can sort the results by price and find a good deal.