Or just make public transportation free...
How much does all the payment system cost anyway? Controls, fines, machines, offices, softwares, time lost to force people to pay while entering...
So, presuming the punishment for not paying the jail bill is more jail: if you can't make at least $182,500 per year, you should just stay in jail forever?
Or pay the fare. Up to you. I don't see why I should pay somebody else's fare, or, for that matter, the cost of keeping them in jail if they insist that I pay their fare.
You — more generally, society — should pay the cost of keeping them in jail because that's what you (society) arbitrarily decided the punishment would be. It's not like there's some natural law saying fair evasion should result in 40 days in jail.
Also, pretty sure life in prison for stealing $2.75 is a violation of the Eighth Amendment.