Thirteen face-down cards, ace to king: one chip buys the difference between any two, and at the end you are paid the product of two cards you pick. What would you pay to play?

Thirteen cards, ace to king, lie face down. For one chip you may choose any two cards and be told the absolute difference of their values, where jack, queen and king all count as 0 and the other cards count 1 to 10. You may do this as often as you like. At the end you pick two cards and are paid the product of their values in chips. What is the most you would pay to play?