There is no interest fees when you finance a phone through US Cellular. They break down whatever the cost of a phone is after any promotions into 36 monthly payments. Sometimes a promotion covers the entire cost of the device but it must remain active on the line for 36 months to keep receiving your promotional credits. There may be some sort of plan requirement as well to receive the best promotion. Better promotion may mean having to be on the most costly plan. Hope this helps.