If you've got the green but not the plastic, Green Dot would like to help. The company offers prepaid debit cards through more than 100,000 retail locations in the US. The MasterCard- and Visa-branded reloadable cards function like credit cards for purchases and cash withdrawals. Green Dot, which has about 4.5 million cards in circulation, partners with Wal-Mart, Kmart, Walgreens, Home Depot, and other retailers to enable its customers to add funds to their accounts. The company's products are designed for people who aren't able or choose not to utilize traditional credit card and banking services. Green Dot makes most of its money from new card, monthly maintenance, and ATM fees.