What happens with shipping things like mouthpieces is that they cause a thickness variation in the envelope and make it more than an inch thick. Some post offices will let that slide but the ones I use won't. The thickness means that is has to be hand sorted. Instead of run through a machine. They charge for that. A flat envelope of the same weight as two mouthpieces is about 3.50 to send. Taking the variation in thickness into account as I have to do means the 1st class price jumps to 9.45
Sending it priority flat rate is 20 bucks.
---------- Post added November 26th, 2015 at 10:03 AM ----------
If a dealer uses UPS then they (the carrier) tack on brokerage, handling, customs, retirement fund contributions, etc.