Hey 1LS! That is crazy expensive! I think the key to getting insurance to cover it is getting a script from your doc. Here's some info I found about getting O2 covered by Medicare Part B...
Oxygen equipment & accessories
How often is it covered?
Medicare Part B (Medical Insurance) covers the rental of oxygen equipment and accessories as durable medical equipment (DME) that your doctor prescribes for use in your home. If you own your own equipment, Medicare will help pay for oxygen contents and supplies for the delivery of oxygen when all of these conditions are met:
Your doctor says you have a severe lung disease or youâ€™re not getting enough oxygen
Your health might improve with oxygen therapy
Your arterial blood gas level falls within a certain range
Other alternative measures have failed
Under the above conditions, Medicare helps pay for:
Systems for furnishing oxygen
Containers that store oxygen
Tubing and related supplies for the delivery of oxygen and oxygen contents
Medicare may also pay for a humidifier when it's used with your oxygen equipment.
All people with Part B are covered.
Hope this is of some help!