@rbreich While I expect that the costs you listed are relatively correct, based on my personal experience, I doubt that the cost of a "unit" of insulin is $98.70. Could you have meant cost of a vial of insulin?
The TLDR: 1 unit of insulin is a typically a REALLY small amount of fluid. No one sells 1 unit of insulin.
My U100 insulin comes in 10 milliliter vials. U100 means there are 100 units of insulin in each 1 milliliter. So my vials of insulin contain 10*100 = 1,000 units of insulin.