Does anyone know where I can get a portable oxygen machine for free?

Hi uall, i am on oxygen, i carry,or pull a tank when i leave my home, My medicare will not pay for a portable oxgen machine. i live in a little dog town, no buses, 1 grocery store 4 bars. I am a disable on disability income, not enough money to buy a lot of extars, I have no family to help me. I would like to enjoy going fishing with out taking my big oxgen tanks with me. No one in this dog town is going to help,me. I put up a sign it gets tore down. no matter where i put it. I ask on craiglist i get ugly/nasty letters. does any one know where i can get a portable oxygen machine for free?