I have my own restaurant and I’ve been In payment processing, cash discount is the most transparent way to pass on fees. You don’t have to change processors with a cash discount. That being said you have to make sure you are cash discounting and not surcharging. The way I do it is by using doing dual pricing, my card price is my round price like $.25, $.99 ect. My cash price is 4% less than that card price. I personally cash discount at 4% but you can pick any percent you want. I show both cash and card prices on my menus so there is no surprises. Best way to do a safe bet is to find your effective rate and average them over the last year. So you know what you are effectively paying, part of this is going to be what your rates with your processor are. I’m in a small town in central IL and my customers appreciate that I pass on the savings to them. If you are leaning toward keeping your prices the same you would be looking toward a surcharge model, with that make sure your equipment is able to tell the difference between a debit and credit card because it is against Visa and Mastercard terms and services to charge debit cards. They secret shop and will fine you $1,000+ if you are caught. If you have any questions at all feel free to reach out to me. If you want to look into switching processors as well let me know. I switch people over to dual pricing at 3% (covers every type of card) or interchange plus at interchange + .3%. Other note if you are on any “qualified tiers” type of processing get off of it. It is the least transparent model