I wish people would quit using priority mail supplies for media mail packages.
The priority mail markings were partially visible along one side of the box, which made it that much easier for USPS to notice the problem.
I debated about contacting the seller, which is what I normally do. In this case, I decided not to worry about the extra $8.22 that I had to pay to receive the package. This was one of those transactions in which the seller bungled the description and got significantly less than the books are worth. The seller charged only $4.00 media mail postage, obviously not aware that eBay allows sellers to use the calculator to charge more than that amount. The seller paid $7.08 to ship the books media mail, taking a loss on postage.
Since the seller undercharged me in the first place, I really only had to pay $5.14 more than the seller's postage cost. This is still too much, but as I stated, the books sold for well below value. I decided not to worry about it.
On the same day that I received this package, I received two other packages. One of the other packages had brown paper wrapped around a priority mail box. That one made it through without getting noticed. If that package had been inspected, I would have had to have paid approximately $9.50 to receive it. So, two out of the three packages received on this particular date had priority supplies misused for media mail.
I received one or two packages during the previous week in which sellers used priority supplies for media mail. It seems to be more common than it once was. I guess these sellers do not realize that they can buy boxes from Uline.com in bulk for under $1.00 each when purchasing quantities as low as 25 boxes.