Insulin is not necessarily a sign of the rising cost of prescription drugs.
Before the early 20th century, people with diabetes were sentenced to death. The researchers then discovered a way to extract and purify insulin that could be used to treat the disease. He won the Nobel Prize for his discovery.
This is a miracle for patients. The patent for the discovery was sold for only a few dollars, so everyone who needed it could get life-saving insulin.
Today, however, a single bottle of insulin is expensive. Most patients use 2 to 4 vials per month (I personally use 2 vials). Without insurance or other forms of medical assistance, these prices can quickly spiral out of control.
Depending on your request, you'll get a different answer as to why insulin prices have gone up so much. Some people blame middlemen. Others say patents on incremental changes in insulin have driven cheaper generic versions out of the market.