As America is an automobile culture, you could break down the class boundaries like this:

  destitute - checks discarded transit cards for remaining balances
  poor - buys monthly transit passes
  lower - buys used car with predatory/dealer "pay here" financing
  lower-middle - buys used car with bank/CU financing
  upper-middle - buys used car with cash, or new car with bank/CU financing
  upper - buys new car with cash
  rich - drives company car leased by an owned business, but uses taxis and Ubers in the city
  ultra-rich - never drives; has on-call professional driver/pilot employees