Good AT&T Smartphone for Straight Talk?

[DarthScabrous]

I'm on a budget unfortunately. I wanted to ask, what are the best smartphones that I can get for under $100? I was gonna get an iPhone 3gs, but if I can find a newer droid for around the same price, I definitely would like to go that route instead.

 

[DarthScabrous]

Maybe i need to mention that I'm not getting a new phone, rather, I'm gonna be looking at Craigslist and Ebay. I'll be putting the AT&T Sim Card in it.