I went into the T-Mobile store yesterday to buy the 521 since my 920 is out for repair. Just got let every one know the price goes up 30 bucks if you're on prepaid. Don't understand why but that's what it is. I end up paying 179.99 before taxes. I think its wrong since they keep advertising 149.99. The only way I could get on that price is if I switched to a non prepaid plan.