Insulin is fast becoming a medication that only the well-insured or well-heeled diabetic can afford. With the price of insulin more than tripling in a decade, some diabetics are having to make tough choices about how to pay for the medication. In some cases, diabetics are cutting back or even going without the drug. Many of the 26 million Americans with diabetes must use insulin daily to treat the disease, or else risk illnesses such as kidney failure and disabilities such as blindness. While American diabetics may have faced monthly costs of $100 to $200 several years ago, some are now grappling with costs of $400 to $500 per month.