I have the WORST Credit known to man, and verizon let me get 2 new phones, for free, with no deposit!
Sprint will require a deposit, but will lower it and put you on a spending limit... As long as you stay below the $300 limit, your service will not get interrupted.. i was a pro at being behind with SPRINT! Also, you will get the FULL DEPOSIT back after the first year even if you sign a 2 year agreement