The Nexus 4 is now only $199 (unlocked and no contract) and will work on T-Mo or AT&T. Now it doesn't have LTE, unless you root it. I rooted mine for just that reason and I'm getting LTE on T-Mo pretty much everywhere in and around 270. Even if you don't, HSPA+ is still plenty fast.
$200 for a premium phone + no contract + $30/month unlimited text & data...can't beat that.
https://play.google.com/store/devices/details?id=nexus_4_8gb