if you use a debit card, a merchant can not charge you a minimum fee
or ANY fee.
https://www.thebalance.com/debit-card-minimums-illegal-or-just-annoying-315267
a screen shot of a email from mastrcard
or ANY fee.
https://www.thebalance.com/debit-card-minimums-illegal-or-just-annoying-315267
a screen shot of a email from mastrcard