My Mom had a lung disease and was on supplemental oxygen for the last several years of her life.
She used a combination of an Inogen One G3 portable oxygen concentrator when she was out and about, and bottled/tank oxygen with a long tube around the apartment.
All of her oxygen supplies came through a local medical supply company and was covered to some degree by insurance because it was prescribed for her due to her condition.
The Inogen One G3 (there's now a G4 I think) was purchased. They're expensive IIRC (hundreds to thousands of dollars), but they work well for the purpose and last for years.
I'm sure there are plenty of medical supply companies near you that could give you more info and options.
