Urgent : Need Portable Oxygen Machine to Breath

I was diagnosed with Pulmonary Hypertension several years ago and it has progressed to the point where I need Oxygen 24 hours a day. 

I am asking for help from others  because all insurance, including Medicare will not cover a Portable Oxygen Concentrator. 

Having an Inogen G4 portable Oxygen Concentrator would enable me to lead a somewhat normal independent life such as driving, grocery shopping, Dr. visits, etc. 

If you are able to donate anything to this cause it would be greatly appreciated.