Apparently we're not reading the same comment. In this example, the rich person pays cash for the 20-pack and probably earns interest on the savings. They have no need to pay interest on a loan. The poor person pays cash for the 2-pack and then pays again next month, and maybe takes out a payday loan to afford the rent after they have to call in sick, and there's your high APR. This is not a benefit. What am I misunderstanding?