More People Use Credit Cards for Small Purchases

This article from the Washington Post, "For Some, No Purchase Is Too Small For Plastic: Fees for Card Use Irk Some Merchants" discuss how more and more people aren't carrying cash, and are using credit and debit cards for purchases under $5. Given that the transaction charge to the retailer ranges from 35 to 55 cents on a $2.25 purchase, profit margins (the article features the local store the Chocolate Moose) get crushed.

Would you recommend a minimum purchase of $5 or $10 to use a credit card? The article says that consumers are rebelling against minimums.