Pagarse sus vicios
 

how can we say pagarse sus vicios en Inglés?
We use it in situations where young people work to get a bit a money to pay his vices, that is cigarettes, clothes, beer etc... without having to ask their family for money.

He/she has a job just to cover or pay for his/her vices.

If the focus isn't on the bad habits and instead is on earning some money, there are other options:

to pay his/her own way
to cover his/her expenses
for spending money

If the focus is on the fact that the money is for vices/bad habits, then I like poli's options.