I don't know if you've found your answers or if this is even relevant anymore. For straight talk,
they offer plans on both the GSM ( AT&T/T-Mobile ) and CDMA ( Verizon, Sprint ) networks.
So that will come down to a few things, mostly your opinion of who has the better network.
As far as I know, and from what I've read, Verizon, and Sprint are rather anal about their
phones and their networks. Verizon phones will default to Verizon as a carrier regardless of
sim used. So a straight talk sim would be useless while anywhere near verizon coverage.
The GSM phones are much easier to manipulate because of the GSM/Sim card relationship.
It is illegal to unlock your devices 3rd party. It is NOT illegal to have AT&T unlock your device.
I've done in a number of times using a 3rd party provider, paying 5 - 10 USD$ who
then goes to the deviced carrier and has them unlock it. In my case I've used iPhone 3GS
for this purpose, and all I needed to do was wait 24hrs then place a T-Mobil sim card in the
device, access iTunes, and poof the phone is unlocked and can be used with any GSM sim
on the planet. Yay.
In regards to you Brittany. My suggestion is IF you can find a used iPhone on ebay that is
in pristine working condition, that is everything works as it should. Disregard the cosmetics.
Cases can be purchased to cover an "ugly" device. Then find one from AT&T, get the straight
talk sim package on-line or whatever retailer near you has them. Put up the minimal cost to
unlock it, (wouldn't pay more than 10) wait 24-48 hrs for whatever service you used to e-mail
you back. Pop in the sim card as per email instructions and there you go. An unlocked iDevice
usable with any GSM sim/network. If you do not care about the technology I know for a fact
that you can purchase an iPhone 3GS already factory unlocked on ebay for under 150.