A bit of a tangent here but did you know that certain states (NY, FL, etc) it's illegal to charge more for credit card purchases? If they do tack it on and you're in one of the states you can have your CC company refund you the surcharge (which I'm sure gets billed back to the merchant) Rasiel
I haven't experienced that myself and it wasn't related to numismatics, but I've seen complaints online that sellers would refuse to do future business with customers who do that.