In US, big pharma realized that they can increase their profits a lot by increasing the price of insulin as the patients don;t have much option here. So, insulin is ridiculously expensive, and those on insurance can't afford spare doses in case they break one.

So, with demand, comes supply. Since pharmaceutical companies were the ones who raised prices and used patents laws to curb any legal competition, only illegal competition remains.

a diabetic training partner of mine told me that black market for the insulin is ridiculously developed