Max Levchin knows a thing or two about money. He helped found PayPal almost 20 years ago, and his new startup, Affirm, is in the business of lending. Affirm partners with businesses so customers can make big purchases in installments instead of taking on credit card debt. He and Marketplace Tech host Molly Wood spoke about the business of money lending and what troubles him about the credit card industry. Listen to the whole conversation here.