Changing-up the conversation a little bit, but staying "on-topic"...
...it has been very well-documented on this website about OP's financial misfortunes over the past few years, which is understood, given the current national financial situation. Lots of Americans are hurting...many of them won't see expensive toys or family vacations, anytime, soon.
If things are truly "that bad" in OP's world, what's the deal with OP mentioning contract cell phones, at all (which, IMHO, given today's less-expensive prepaid options, is a huge waste of $$$ -- plus, if the son has an "upgrade available" to him, that usually means someone in the family is under contract)?
My friendly BB advice to OP - you need to do some "non-DIS" research on the internet about the prepaid marketplace (Howard Forums immediately comes to mind), your son could get a nice, spiffy new phone that does everything he needs it to do, and, in many cases, at a much lower price than what you're dishing-out, right now.