It's not the version with Nvidia's G-Sync technology baked inside, but Acer's B286HK 28-inch 4K Ultra HD monitor is selling for just $349 on Newegg today. That's a pretty hot price for a 3840x2160 monitor that's capable of 4K video at 60 FPS over DsiplayPort 1.2. It's an especially good deal when you consider its original selling price of $699, though we've seen it on the street for as low as $450 (Provantage) prior to today's sale price.
Quite a bargain now.