Q: iphone4

Since the phone still seems to be locked to AT&T, you'll have to have a SIM from that carrier to be able to use the phone again. It will not work without another SIM unless it has been unlocked by the AT&T. Check this article for more details:

iPhone: About unlocking

If the software of your phone has been modified to let you use another SIM without unlocking it first, you can't use the phone anymore until it has been unlocked.

Unauthorized modification of iOS has been a major source of instability, disruption of services, and other issues

Any other active SIM card from AT&T should work, if it supports the iPhone.