There's actually no way to give away free copies of the app in the marketplace after publication, devs get 50 codes tops for promo/etc.

Android I guess you could spread the APK around.

This really seems an odd direction to take on this whole process - unless you're buying devices to test on this seems more like something that would be taken on in someone's own time and profited from after release rather than a cash up front project. Do you have dev costs/subcontractors to pay on this?