Portable oxygen concentrator vary in price form around five hundred dollers for an inexpensive unit to multiple thousands of dollars for more expensive units with more features. The price varies pretty widely, but your looking at spending at least 2-3 thousand dollars. If your willing to buy used, you may be able to go down to around $1,000. It depends on where you buy it and what kind you get. You can pay anywhere from $250 to $4000 for one. The more state of the art brands will obviously cost you the most money.