(Let me start off by saying that even though I'm 26 and pretty tech savvy, I know next to nothing about cell phones. I'm used to buying cheap pre-paids and thats about it, so feel free to dumb things down if need be)

I got these phones, both are great, not sure which I'll keep yet.
Anyway. The Finesse and Intensity 2 are both "CDMA" which I've learned means they have no SIM card and can't simply be swapped out for another. I want to be able to change provider and get a new number. I'd really like to get on a pre-paid plan. Something like NET10 or Straight Talk since its unlimited everything for approx $50/month.
The Finesse is currently on Appalachian Wireless.
The Intensity 2 is on Verizon.

Is what I'm wanting possible? How would I even begin to do this?