You won't get prison for the inability to pay... But you might get prison for deliberately not paying even if you can pay, or for lying on government forms/falsifying records.
I could have constructed my previous comment better: yes, nobody's going to prison for sime non-paymens but rather fraudulent activity and failure to compensate the victims of such actions.
The US governments love putting people in jail for inability to pay fines. But mostly <$1000 fines and poor people.