There are some charities that will help an individual pay their rent. But there is no need to approach such charitable institutions as the US government offers financial assitance to those who do not have enough money to pay for their rent. There is a program called the Housing Choice Voucher Program that will allow certain qualified individuals from being entitled vouchers that would allow them to pay for their rent in part or in whole. For more information on the other types of rental assitance that the US government provides go to this site: http://portal.hud.gov/hudportal/HUD?src=/topics/rental_assistance
Depending on where you live, you may be able to receive help paying your rent from a local community action agency or charity. Community action agency's receive federal funding to provide assistance for people who need help with food, rent and medical expenses. To find more information on community action agency or charity, visit http://www.needhelppayingbills.com/html/community_action_agency.html#nonprofit.