Bank for the Poor (http://www.grameen.com) has established a good economic model for banking to attempt to overcome poverty in India. You and a local group of friends can get a microcredit loan based on being shamed into returning the money or your friends will know if you are a deadbeat. The unfortunate downside to this model from working in the US is that the poorest among Americans do not know shame. Loan someone from India $20 and they go start a business. Loan a beggar $20 in America, and they go around the corner to get high or drunk.
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Grameen Bank (GB) has reversed conventional banking practice by removing the need for collateral and created a banking system based on mutual trust, accountability, participation and creativity. GB provides credit to the poorest of the poor in rural Bangladesh, without any collateral. At GB, credit is a cost effective weapon to fight poverty and it serves as a catalyst in the over all development of socio-economic conditions of the poor who have been kept outside the banking orbit on the ground that they are poor and hence not bankable. Professor Muhammad Yunus, the founder of "Grameen Bank" and its Managing Director, reasoned that if financial resources can be made available to the poor people on terms and conditions that are appropriate and reasonable, "these millions of small people with their millions of small pursuits can add up to create the biggest development wonder."

As of March, 2011, it has 8.36 million borrowers, 97 percent of whom are women. With 2,565 branches, GB provides services in 81,379 villages, covering more than 97 percent of the total villages in Bangladesh.

Grameen Bank's positive impact on its poor and formerly poor borrowers has been documented in many independent studies carried out by external agencies including the World Bank, the International Food Research Policy Institute (IFPRI) and the Bangladesh Institute of Development Studies (BIDS).

You mean, is it possible to be the poorest person in the world? Well, a lot of people have zero dollars (or any kind of currency). After that, what they consider to be items of value varies per culture - perhaps they have animals, or clothing, or a shelter of some sort - all could be considered forms of "wealth" to that culture, or to that person.

But to answer your question, generally it is accepted that Buddha gave up all earthly possessions in order to become more enlightened. So he's a pretty good candidate, as well as many of his followers.
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