Me and my family are going on vacation in Florida in a few weeks. We live in Canada. The roaming charges for my current phone (with Koodo Mobile) are ridiculous, and the phone company I'm currently with has no sort of "travel packs" or roaming/long distance minutes/messages to buy. I am thinking of buying a cheap ~$40 cell phone unlocked, that takes SIM cards, and putting it on a prepaid "plan" with AT&T or something while I'm there. My question is, will AT&T, or other companies, let me use any cell phone with their prepaid plans?