Same happened to me. A test with insurance cost $3000 with insurance. They paid $2250 leaving me with $750.

I asked how much it would be without insurance and they quoted me $350.

My understanding is that the insurance does not actually pay the price they tell you in your explanation of benefits.

So if it's any comfort, I'd guess your insurance wasn't getting billed on top of that. They probably paid $15 and pocketed your copay.

Some might call this "keeping two sets of books", but apparently it's par for the course here in the glorious USA.

Up until recently [0], it was common for insurers to have rules preventing health care providers from telling you when it was cheaper to pay cash.

[0] https://www.aarp.org/health/drugs-supplements/info-2018/gag-...

Did you switch to getting it without insurance?

If it's any consolation, the insured patient payments are subsidizing the non-insured cash cost.