Recently a merchant told me how they had just switched their processing through Bob, who told them they were going to save 50% on their processing fees. Processors all work off the same cost, which is interchange. Interchange is the money the banks make for extending credit with the credit cards they issue. Visa and MasterCard add approximately a tenth of a percent on top of interchange. The processor makes another small sliver on top of that in order to service the merchant. Nobody, not even the scummiest of credit card salespeople on the planet, are marking up the costs 100%. In the case of 50% savings, Bob is misrepresenting the comparison in order to get the sale.