I've heard they're about $3,500USD and aren't covered by insurance. For something that I'm unsure would solve the problem, it seems a bit much. If it were 1/10th the price, I would just try it.

Seems like the 3d scanning my kids had for their braces, plus 3D printing could make it less expensive, at least for a prototype device to just try.

I should try that "tape over the mouth" thing to see if it helps, particularly as I'm super mild apnea, but I'm expecting it won't really work with my beard.