Cash discounts are acceptable but this DQ is clearly charging extra for using a CC (they even have a little sign on the register that says .39 extra for credit cards), I paid with a credit card the first time and indeed it was 39 cents more than the advertised price.

I filed a complaint with BBB and DQ responded within an hour saying that the particular location was independently owned and that they would contact the Owner/Manager.

My guess is that the Owner/Manager of that location doesn't know much about CC Laws.