Rent one, as in for use in your home? Never heard of it. Buy one for around $70K US. Insurance covers treatments in one for a limited number of medical issues, but I've not heard/seen that long covid symptoms are one of those issues. See: https://www.hyperbaricmedicalsolutions.com/blog/how-much-does-hyperbaric-oxygen-therapy-cost

I am renting mine from "Affordable hyperbaric solutions" at $1050.00 per month. It gets to 1.5 Atmospheres (the ones doctors have are 1.7 and above). I chose a small chamber that looks like a capsule, 9 feet long and almost 3 feet tall. It doesn't feel claustrophobic to me. I mostly lie down because I can barely seat in there. You can use your cell phone inside, watch movies, etc. although for me it is the best time to meditate. My neurologist said I could use it twice a day for about 1 hour. I'm out of town now but I can send pictures when I get back.