They can try and charge whatever interest rate they want, because I'll never pay a penny of interest. I use CC as a substitute for cash ONLY.
It's against the cardholder agreement to charge a surcharge for using it. They can close your Merchant Account for doing it, but it's not being enforced. However, I signed that merchant agreement, so I don't charge a surcharge. HOWEVER, I limit the size of the purchase that I will accept a card for. I looked, we paid over $60K in CC acceptance fees last year, and that's still limiting purchases to stuff that we had a high enough margin on to allow.
Bogus, you'd never got past me on that one with the Van - the only person that got hurt in that deal was the Dealer. They usually only make 2-3% on a sale if you priced them right, and that cc fee took all their profit. I tried the same thing once; the salesman was all for it; about 15 minutes later the business manager called and told me he just couldn't do it. I said "I know, I just wanted to see if anyone was paying attention" and wrote him a check which I'd planned to do in the first place.
I won't take AMEX because they want 4% to accept and they can shove it. I pay about an average of 2.49% to accept VISA,MC,Discover.