Why is the T-mobile iPhone so expensive?

With AT&T, Sprint, and Verizon the 32 GB model is 299. From T-mobile, it is 749. Isn't that ridiculous?

The other carriers subsidize the price by making you sign a two year contract. T-Mobile doesn't bind you to service for two years in exchange for paying full retail price for their phones

Contract vs no contract.
T-mobile doesn't do contracts any more… The reason ATT/spring/verizon are so cheap is because they lock you into a 2 year contract and are guaranteeing they will pay off that $400 difference. With T-mobile you are not guaranteeing them anything… So they have to make money off the phones.

$749 is retail pricing (go look at the apple store for off contract price)

if you are going to go with T-mobile, go with a nexus 4. At $350 off contract its the best phone you can buy for the money. This way, you save money on your monthly bill without much extra out of pocket up front.

The Tmobile iPhone is actually cheaper in the long run; just because you pay full retail price for the phone doesn't mean it's expensive. You pay $200 down (or whatever they make you pay) and then make monthly payments on the phone; with AT&T or Verizon, you pay $200, plus x amount for 24 months ($110 on Verizon for 4GB of data, which is what I would use, over 24 months is $2640, significantly more than what I would pay for on T-mobile which would be $249 down for the 32GB model plus $70 a month for unlimited everything and $20 per month to pay the device off over 24 months is $2160). Or, if you wanted to pay off the phone in 12 months, with T-mobile, using the same math as above, you would be paying $70+$40 per month on the device, which is $1320 in one year, half the cost of what you would be with on Verizon. The great thing about T-mobile is that you don't have to be locked in to contract anymore, and with carrier subsidies gone, phones are going to be cheaper in the long run.

$299 is contract price and $749 is no-contract price.