I Have Been Taking 60 Mg Oxycondone. For Years. Now

I have been taking 60 mg Oxycondone. For years. Now I am on Medicare and I can't afford to pay for it any longer. What other pain med could I go to that would be as effective that Medicare would pay more on be cheaper. I am a chronic pain paition. Four lower back surgery'es they have removed all disc but one in lower back. CAN YOU HELP ME.