Activating iPhone 3GS?

@Toaddiddy89 - welcome! That's a great question. The answer to that is yes, you can use the iPhone 3GS on AT&T's network if it was made for use on the network or is unlocked. You would not have issues as far as adding it to the account. However, be wary buying the phone from a third party can impose some issues like the phone being blacklisted, locked, broken etc. You can get the latest and greatest iPhone on ATT Next and paying $27.17/monthly in top of your plan. 🙂