I would suggest 42 cents plus the 20 cent surcharge for non-machinable. I just had this debate at the post office yesterday. When I came home I checked the definitions on the their web site. The rigid factor does not make it a package... It makes it non-machinable. This seems to be a common problem and in the future I won't pay it.

I'm planning on asking them to show me a rate table that supports what they say. I think they are totally ripping people off and I think they know it. I'm going to print out the page from their web site and carry it with me. Wish me luck!