Oxygen sold in hospitals can be reimbursed by medical insurance, but it is more troublesome. I recommend you an oxygen concentrator.
Physical oxygen generator (Ocean Oxygen Home Oxygen Generator): It produces oxygen when plugged in. It is small in size, light in weight, has a long life (about 40,000 hours), consumes less power, and has the disadvantage of being noisy ( Below 35 decibels, it will basically not affect life), the machine price is 2,008 yuan. The effect on promoting sleep is particularly obvious. Can be used 24 hours a day.
Oh, and I suggest you not to use oxygen bags or bottles, because medical emergency oxygen will cause damage to your lungs and may cause oxygen dependence or oxygen poisoning. In short, it is not recommended that you use any oxygen with an oxygen concentration higher than 40%.