[derefr]

IIRC Visa (at least) has a rule stating that a business can’t charge more for Visa card transactions than cash transactions, nor can they have a minimum purchase for Visa card transactions (unless they also have the same minimum purchase for cash transactions.) If they find out a business is doing these things, they’ll stop allowing the business to accept Visa (even through intermediaries like payment processors).

[intelekshual]

This is no longer true as of ~2013.

See rules on surcharging: https://usa.visa.com/dam/VCOM/global/support-legal/documents...

And minimum transaction amounts (minimum can't exceed $10): https://usa.visa.com/dam/VCOM/download/merchants/minimum-tra...

[kyllo]

It may be against Visa's ToS, but it's still a very common practice, especially among small businesses, probably because of enforcement challenges.

[exclusiv]

I've reported a few businesses and it was an easy process. I don't think it's an enforcement issue; more of consumers not being informed that the merchants shouldn't be forcing them to increase their basket size to a min amount and not knowing that it's easy to report.