If I buy an unlocked iPhone 5, can I use my AT&T micro SIM card?

I just have an android cell phone and It is a go phone with AT&T that I will be giving to my grandkid. I do not want another 2 years contract since this go phone will remain in my name.

Yes if it is unlocked

If you buy unlocked iPhone 5, it will work with AT&T. I'm pretty much sure it will work with any carrier with micro SIM card.

No. The iPhone 5 uses a nano SIM so you would have to cut the micro SIM card down in order to use it.

While you may be able to use it with AT&T's smartphone plan, you would not be able to use it on a Go Phone account. Specifically, the prepaid data component of the plan does not support iPhones. To reconfigure the phone to do so would alert AT&T.

I think your best bet is to get the phone through Straight Talk. They are a prepaid provider that supports the iPhone. However, because they are a no contract service, you would not be bound to them.

That said, their service is a great deal. They offer Unlimited Talk, Text and Data for $45 a month, which, I believe, is significantly more bang for you buck than the AT&T smartphone plan offers.