i use at&t go phone.
I recc to pre-pay $100. Pay cash if your want total anonimity. Its good for 12 months. Less than $100 increment is good for 3 months i think
10 cents voice.
20 cents text
data is 1 cent 5kb....
i recc to go to local starbucks & use the free wifi.
as for the physical phone itself, you can go with a $30 crappy phone or buy a used decent phone on ebay with a sim card. Keep the phone if for future reference as a small investment. If you were here, i would give you a pile of my older phones to use