Look in the "packages" section of AT&T's GoPhone website and you'll see something interesting: phones that are free or better-than-free with an airtime card. There are two ways that airtime is included, however. I've marked phones with an asterisk that have the airtime preloaded. The ones with no asterisk have the airtime as a separate card, for even more bonuses and savings!
LG CG150* - $40 including $25 in airtime
Nokia 2610 Refurb - $25 including a $25 airtime card
Samsung a117 Refurb* - $29.99 including $25 in airtime, $40 including $50, $80 including $100
Nokia 2610 Refurb* - $40 including $50 in airtime, $80 including $100
Pantech c120 Refurb* - $25 including $25 in airtime
Samsung a437 - $10 w\$25 airtime purchase
Pretty good deals, if you ask me. Granted, you may or may not have to open up a new line of service to take advantage of these deals, but they're really good anyway. Not bad at all in my opinion for a non-contract cell phone.