thats what i thought about $15 is there like a second class service available? as the seller stated first class with customs number usps, there must be a second?
You get a tracking/customs number with first class. Priority costs more but is pretty much the same in regards to how quickly it gets to you. Below is a link to the class of mails.
For the most part he is trying to get an extra fiver or more out of you. He may be guessing as well as it is sometimes a gamble when you go to post stuff as far as price.