The Nexus 5 was a watershed moment for the Nexus program. It was the first device from Google that didn't feel like it was making any extraordinary sacrifices in the name of value or openness. More than two years later, many people are still using the N5 (judging from AP site statistics). If you are not among them, you can pick up the venerable Nexus 5 on eBay today for just $139.99, which seems like a great deal.
This is a refurbished unit, but that's kind of what happens when a phone has been out for a few years. This is at least a 32GB model, and you have your choice of white or black versions. The Nexus 5 is still a reasonably fast device, and it runs Android 6.0. That's more than you can say for a lot of current-gen phones.
The listing is for a D820, which is the North American model. That means full support on AT&T, T-Mobile, and Sprint. The N5 comes with free shipping in the US and tax is charged only in Florida. The seller will ship internationally as well if you don't mind paying for it.