iPhone owners must bring their used iPhones to a retail outlet in the U.S., Canada or Puerto Rico where a sales representative will evaluate the device and decide on the amount.
The gift cards that result from an iPhone trade-in can be used for anything Microsoft sells in its stores, including its Surface tablets and third-party PCs.
Other companies such as Gazelle and NextWorth pay between $190 and $210 for a working 16GB iPhone 4S on AT&T's network, and between $290 and $304 for a 16GB AT&T iPhone 5.
Microsoft also has a buyback program that operates online, and has already debuted an iPad buyback program.
The latest iPhone buyback program expires Nov. 3.