Although it's a bit more expensive than $150. Last year's Google flagship device the Nexus 6 can be bought outright on amazon for $250.

http://www.amazon.com/Motorola-Unloc...ywords=nexus+6

It's a used phone but comes with a factory warranty and is still among the best specd phones available. Since it's a "Google" phone it gets the latest updates first, and doesn't have any of the carrier or manufacturer bloat wear that often gets added by the respective android phone manufacturer(Samsung, HTC, etc) add before they push the new updates. It's "vanilla" android.

I've had it since it first came out and love it. Still just as fast as anything out there.