Right now, eBay is running a pretty sweet deal on the AT&T version of the Galaxy S4. It's the SGH-I337, however it is unlocked. So while it is the AT&T variant, it will work on other networks. The Galaxy S4 features a 5-inch 1080p display, Qualcomm Snapdragon 600 processor, 2GB of RAM, 16GB of storage, and a 13MP camera on the back. It's also running Android 4.4 KitKat. You can pick one up from the link below.
Samsung Galaxy S4 - $279.97 (eBay)