Is credit card surcharging legal in Minnesota?

Usually yes, with conditions. Minnesota allows a credit card surcharge but attaches rules you have to meet. Minnesota permits credit card surcharges with a statutory ceiling and an oral-plus-signage disclosure rule. Minn. Stat. § 325G.051 allows a surcharge so long as it does not exceed five percent of the purchase price and the seller informs the customer — orally at the time of sale and by a conspicuously posted sign in person, or by a conspicuous notice during the sale, at the point of sale, on the order summary or on the checkout page online. Minnesota's price-transparency amendments to its Deceptive Trade Practices Act separately require advertised prices to include mandatory fees, which matters if you accept credit cards only.