ganha = win or wins ... but actually it also means earn ... it would be helpful to have that as one of the definitions!
Wins is only for the 3rd persons in the present simple and they are: he she it Example she wins 30 per hour . And yes earn should be acepted
"How much do you earn per hour?" would seem like a more natural translation into English.
Please add earn to the hover if you don't want people to continue adding comments