I ordered self-pay CTX and P1NP Bone Turnover Markers (BTM) tests through Jason Health 2 days ago. My doctor was not interested in ordering BTM tests anyway. The cost through JasonH is very reasonable for me.

$80 for the P1NP, $50 for CTX. Blood draw costs $20. Links here:
https://www.jasonhealth.com/test/16609-procollagen-type-i-intact-n-terminal-propeptide
https://www.jasonhealth.com/test/17406-collagen-type-i-c-telopeptide-ctx
I plan to have the blood draw in 4 days and post more on this forum about the whole experience when I get my results. So far it has been very good, except that the preparation instructions for one of the other tests I ordered were lacking. I rang Jason Health to ask and they emailed me links to the details of prep for each test and answered my questions.