My project is ready to for some live testing. I've heard against using your own iPhone to test so I'm curious if there's another way to get an iPhone for development other than simply buying in Apple store. So question is: what's the cheapest way to get my hands on an iPhone I can use purely for development?
I don't see how there would be a problem with testing with your own iPhone - all the apps are sand-boxed and should not be able to 'hurt' any other part of the system. There might be some memory fragmentation and crashes because of your testing, but a reboot should get you back to normal.
You can always buy a cheap(er) 1st Gen. iPhone in eBay or Craig's list or get an iPod Touch and hardcode the GPS/Core Location programming for preliminary testing.
Lastly, get Beta testers. Get their Unique Device IDs (UDID) and compile copies for them to test for you.