Why not offer the customers an option? Download the game free with limitations that you can buy in game stuff to get around, or pay $5 and have the limitations removed (or an unlimited amount of the in game currency whatever. Sounds like the next logical evolution of shareware, to me.
You would probably get a lot of people who would download the game free, try it out, maybe make some in game purchases, then decide to upgrade to the $5 version, so you would make $5 + whatever they spend on in game items before upgrading. (Or whatever price you decide to charge). You won't be making hundreds off anyone, but you'll probably get more bites overall.