Update: The deal is back, this time from a different seller buydig.
New top-of-the line smartphones naturally come down in price over time, but the Galaxy S4 has shown a remarkable tendency to go on sale early and often. This time it's on eBay for $575, which is $25 less than last time. Not bad for a device that usually sells for nearly $700 unlocked.
This is the unlocked 16GB version of the device, meaning no LTE. You're limited to HSPA+ 850 / 900 / 1900 / 2100. Those on CDMA carriers won't be able to use this particular device at all. While the US variants of this device have a Snapdragon 600, the i9500 runs on the Exynos 5 Octa 5410 ARM chip.
Otherwise this is the GS4 you know and love. There is no carrier crapware, but all the Samsung stuff is included. As such, about half of the storage is used out of the box. Might want to grab a microSD card while you're at it.