How much does a 30-day supply of insulin cost?

Could you please elaborate on the factors that might influence the cost of a 30-day supply of insulin? Are there any variations in pricing based on the type of insulin, the dosage required, or the location where it's purchased? Additionally, are there any programs or discounts available to help patients manage the cost of insulin? Understanding these details would be crucial in determining the overall cost of a 30-day supply.