Refurbished Gophones are a great way to get a full-featured phone at a low price without signing a long-term contract. Note: Their term for refurbished is: "Certified Like New".
Refurbished handsets carry a 90-day manufacturer's warranty from the date of purchase.
For AT&T warranty claims after the first 30 days you can call 1-800-801-1101.
The easiest way to find deals on their refurbished phones, is to simple go their list of Gophones. On the left column there will be a radio button you can select that says "Certified Like New" and that will show you just those handsets. You can then also arrange the list by price from high to low or low to high.
Here are the current refurbished handsets available. Most are smartphones except for one flip phone.
I've ordered a couple of refurbished phones from AT&T in the past like the Nokia 2330 and Nokia 2720 to
review for this site. The only difference is that the refurbished phones don't come in a plastic blister pack and are therefore easier to open. I did not detect any physical difference in the phones themselves.