No plan I know covers trimix. Also I believe it is not FDA approved as is, since it involves mixing three medicines.
I was originally directed to an online source in FL. The first time the med was delayed and arrived no longer cold. It still worked, but I thought, "Wouldn't it be better to get it locally?" So I called around and found there was a compounding pharmacy (one) in our urban area =< 1 million that would make it up for me. It ended up actually being cheaper when including all the costs. I go to the pharmacy and they mix it after I arrive while I wait. It costs right at $100 per vial. Number of doses is dependent on dose of course, but let's say possibly between 50 and 100, so it's limited by shelf life of the medicine. If you follow the pharmacy guidelines to use it in a month, that might be 15 or fewer doses. As I noted elsewhere, I use it for about 5 months. That means my cost is about $1.50 per dose including the needles, rather than >$6. While I also get 10 needles with it, I buy needles from Amazon in batches of 100 for $17, so it's a fairly trivial expense and I get consistent needles.