If it's in a #10 and it is not too thick (I can't remember the thickness allowed off hand) then you payed the right amount. It can't exceed a certain thickness even in a #10 envelope. But I agree they do not remain consistent. I only lost one argument with them when they found out I was mailing the American Casino Guide via Media Mail. On the site the pure restrictions state no coupons allowed in books. It is a book with an ISBN # but it does have coupons.

That reminds me I need to sell the last case I have of the ACG 2010 book!!!