It isn't different from any other prisoner. In many states you leave prison owing them back rent. Maine at least charges as a percentage of the prisoners income, rather than having them build debt.

https://www.npr.org/2022/03/04/1084452251/the-vast-majority-...

Maine: https://www.corrections1.com/finance-and-budgets/maine-lawma... "the state can deduct up to 20% of their income — 10% for room and board, which is sent to the state’s general fund, not the Department of Corrections , and up to 10% to cover transportation provided by the department. Since 2020, the state fund has collected a total of $2.4 million.