Be sure to check that you are getting it through a provider that works with your insurance company.
After my first sleep study I got one via a company the hospital gave me the name of. Not only were they NOT on my insurance's approved list - they were also totally disreputable. They charged me sales tax on the total amount (my insurance paid a portion). This was in CA where there is NO SALES TAX on CPAP. I even had an attorney verify that.
I wonder how many people they scammed on that one - they sure weren't sending the money to the state. I did two things - reported them to the state and immediately changed providers.
The second provider was totally covered by my insurance and gave me MUCH better service (in addition to not cheating me). I had a technician come out and fit me personally, was given prompt service, etc. The first provider just mailed the stuff to me.
I had a lot of problems and had a humidifier added plus was switched to BIPAP (which does not blow in as you exhale). Unfortunately none of it worked for me, and I eventually had surgery.
What no one ever told me (too polite?) was that losing weight is one of the best things to do and helps many people with apnea. It's kind of a vicious circle - with apnea you can be too tired to exercise and eat right. The extra weight can (not true for everyone) contribute to apnea.
After I had the surgery to fix the apnea I became my more active self and lost the weight without even really trying to.