Nothing, anymore, in the US at least. A court case a few years back resulted in retailers having the right to offer an "X% off if paying with cash" discount to

Nothing, anymore, in the US at least. A court case a few years back resulted in retailers having the right to offer an "X% off if paying with cash" discount to customers. But they are still barred from doing the reverse (line item for X% more for CC transaction on the receipt).