It's possible to obtain the hosting fees through donations from happy customers 
Probably by displaying a messege asking for a donation to people that won significant amounts of money and placed a withdrawal.
Surviving off donations is not a good business idea. Maybe if you're trying to be non-profit like Wikipedia, but then you still have to have a large enough bankroll for a seemingly pointless investment. Would you seriously think about having millions of dollars in a casino where you don't even have any idea if you'll profit in the future?Probably by displaying a messege asking for a donation to people that won significant amounts of money and placed a withdrawal.