I might have to read up on it again. but I remember the JUMP fee is $10 which you have to enroll (required) in order to qualify you for an upgrade every 6 months. in which case if it's a fee you're required to pay, it's an interest. otherwise without it, paying the equipment fee of $20 every month from month to month and upgrade every six month would be a good deal, in THAT case you're not paying an interest, you're just paying off the face value of the phone indefinitely.
it really is a FAT 50% interest. based on two years of equipment payment of $20/mon, that's $480 in two years per phone plus $240 of interest, that's a total of $720 dollars every two years for a phone. or if you divide that by every six month, that's $120 plus $60 of interest, at a total of $180 plus the remaining value of the face value of the phone should you stop using JUMP. I don't know about you, but smart phones don't depreciate anywhere near $180 every 6 month. they're essentially charging you an interest of $60 every 6 months on top of the depreciation rate of the asset. so theoretically they can salvage the asset and still make money on the interest. it's financing at its best, that's intrinsically nothing new. (face value + interest x years with depreciation). and the longer you stay with Jump, the amount racks up . I should buy some t-mobile stocks.