The Galaxy S6 has only been out for a few months, but we're already seeing some solid deals on the international variant around the internet tubes. Today it's popped up on eBay Daily Deals for a mere $579.99. That's $50 less than the last time we saw it.
This phone still sells for well over $600 on Amazon, but you can only get black or gold models from this eBay deal. It should work fine on any North American GMS/LTE network. It has all the LTE bands you'd need on AT&T, and it has bands 2 and 12 for T-Mobile in addition to the usual AWS. It is, however, missing T-Mobile's main HSPA+ band (AWS). As long as you're in a 1900MHz re-farmed area, you'll get 3G just fine on Tmo.
Samsung region-locks even unlocked phones, but presumably the seller has made sure these devices will work in North America. Just keep that in mind. You get free shipping on this deal, and there's no tax unless you're in Missouri. Limited international shipping is available as well.
- Galaxy S6 on eBay