How much does a Birkin bag cost?

Could you please clarify the price range for a Birkin bag? I understand that they are considered a luxury item and can vary greatly in cost depending on factors such as the material used, the design, and the availability. Is there a general starting price point that one could expect to pay for a Birkin bag, or do prices vary so widely that it's difficult to give a definitive answer? Additionally, are there any specific factors that tend to drive up the price of a Birkin bag beyond its initial retail value?