You should go in with the expectation that your gross revenue will be zero unless you get lucky. There are plenty of people trying to sell their games and the probability of being one of the more successful ones are slim at best. Don't quit your dayjob.
Agreed! I mostly just put out my stuff as free, turns out you have a higher chance of making money getting tips from free games then from paid to play. Or atleast that's my case anyways but yea best to go into expecting nothing so you're pleasantly surprised. I think smaller projects should be free to play with optional donations/tips and only the larger projects should be pay to play (with a free smaller demo).This method seems to work for me and various other peeps, this is especially lucrative if you're going for a certain niche type of games, :3