I am familiar with the notion of listing insulin as a life-saving drug and making it free, but I can't speak to the experience in specific jurisdictions that have done that.
Again, insulin is needed every day for someone with type 1 diabetes to avoid a fatal complication called diabetic ketoacidosis, as you know. Adequate doses of insulin are needed consistently to prevent long-term complications. So it's both short-term gets some, at least, and long-term gets adequate doses in order to forestall those long-term complications. Making access free would surely improve the appropriate and adequate utilization of insulin.