What will the Interest Rate be on an non-subsidized iPhone?
There is no interest, you put a down payment and pay the monthly rate (Commonly, something like $100 down and $20/mo for 20 months). However, you have to have a contract, and you're required to stay on your monthly service plan or you'll get charged the remainder of the full price of the phone, I think.
Maybe this t-mobile variety is genius, but bad news for apple because it encourages people not to upgrade after two years.
On the contrary, I think it is great news for Apple, because people who really want that new iPhone will just sell theirs and then buy a new one. They won't necessarily feel obligated to keep the phone for the remainder of the 2 year contract.
However, T-mobile is not pushing prepaid plans, they're pushing "Value Plans" that require 2 year contracts. It doesn't matter if you buy the phone outright and sign up for service, or if you purchase through a payment plan, you still have a 2 year contract.
The value plans
are cheaper than the equivalent subsidized phone plans from t-mobile, at&t, verizon, or sprint, but they aren't any cheaper than the ones from MetroPCS, Cricket, Straight Talk, Virgin, or others (that I know of). However, value plans have free mobile-to-mobile and at&t roaming, which the other companies never give you.
That said, it's a 2 year contract with no phone subsidy. On the plus side, you only have to have that contract once, from then on you're good to go (unless they give you an incentive to renew the contract).
From experience, they do give incentives to renew contracts, EVEN with value plans. It's not a $300 phone subsidy (which these days is trending down towards a $150-200 subsidy, see Nexus 4s! OUCH!) - sometimes it's a free month of service or something small like that.
However, their loyalty department has been really good to long time (and not so long time) customers with renewal subsidies. Many times you can (almost) match good AT&T/sprint/vzw deals for new customers, and have a service plan that costs a hell of a lot less.
So I'm going to miss the subsidized plans! My last 2 renewals were good, and I'm paying the same as a value plan would cost - not including monthly payments for the phones lol. On the other hand, their coverage is nowhere near as good as Verizon (although, not necessarily any worse than AT&T or Sprint, sometimes better depending on your region) but you know, you get what you pay for! Their customer service can be hit or miss as well, but again.. I'd rather deal with them than AT&T lol.