The 2nd generation Moto X is one of the best devices you buy running stock Android, especially if you're among those that consider this year's Nexus to be better sized for giants than humans. The device still sells for roughly half a grand, but if you're willing to pick up a refurbished model, you can current get one for just $250 on eBay.
These units are unlocked AT&T models, so you're free to take them to your GSM carrier of choice. Naturally, you will have to do without your own customizations. These are black phones, and there may be some signs of previous use, so you're not going to walk away with the most extravagant Moto X on the block. There are no choices on the memory front either. You get 16GB of storage.
Shipping is free, but the seller is only willing to send these units to most of North America and Europe.