Oxycodone treatment options that dont cost an arm and a leg?

So my doctor has had me on oxycodone 10mg 4-6 times a day for the last two years. The medicine no longer works like it used to so I am constantly in pain anyway, and have to take a pill at 3 AM every night just to fall back asleep, otherwise withdrawal keeps me awake and miserable.

I am pretty fed up with having to take pills every day to be normal now, even if I am not in pain due to the dependence this medication creates with your body. My doctor said I would have to go to rehab to get off the medication she put me on, so I called them and they want 400$ up front! That is with insurance! I barely make enough money as it is to pay for my prescriptions and doctor vists, so there is no way in hell I can afford that.

I would rather deal with the pain and not have to take pills, but i'm already knee deep in crap so its a bit late for that. Sadly, I dont really have a choice other then stay dependent and feed the doctors and pharmacies the last of my pay check.