If you're in the market for a cheap iPhone 4, you may want to call your local Radio Shack. A leaked document provided to 9to5Mac suggests the electronics retailer still has inventory of both the 8 GB and 16 GB models.

The two iPhone 4 models are available for US$99 with a new two-year contract. This offer extends to all US carriers with an iPhone which includes Sprint, Verizon and AT&T.

Supplies are limited so you may want to move fast. If you're on the fence about buying an iPhone 4 or an iPhone 4S, you can check out Chris Rawson's article that highlights some of the differences between the two handsets. You may also want to wait for the iPhone 5 which is rumored to launch later this year.