I recently went to the US for a few weeks. My Nexus 4 worked just fine with a US SIM from T-Mobile. $70 for a month for voice and data was worth it, and everything worked quite nicely. Big +1 for unlocked products!
Do you have a contract? That maybe why price you pay is cheaper.
Seems like parent was only in US for a short period of time, so he probably didn't wanted to sign a, say 12 months, contract.
It's a prepaid plan with T-Mobile. No contract. Every Nexus 4 owner loves to talk about it. Go look at the Nexus 4 subreddit, it's a circle jerk of people who are "beating the system" by using a low-end phone on a sub-par carrier and getting "unlimited data".
Nice troll. You can get the same plan with any GSM phone.
T-Mobile is about the same as Sprint and AT&T, and all are sub-par to Verizon. But what's nice about T-Mobile is that you get unlimited data, whereas with Verizon, you'd better cash in your fleet of 777s to afford your bill.
And +1 for non-contract-friendly carriers like T-Mobile. Anytime someone bitches about their phone contract (here in US), I ask if they're willing to switch to TMO like I did.
Some have good reasons why (mainly coverage, tho TMO is getting better), others are forced to question their contract policy.
Right now I'm paying monthly at TMO what I paid on Verizon+AT&T for me and my wife - except I now get 3 other smartphones on the plan for the same price, all with their own 500M data pool.
Once the new phones are paid off (i.e. equipment loan), I'll be paying just a bit over what I did for just one of my lines for all five lines I'm paying today. And no other carrier in the US has HD Voice.