More sound and fury on the $10 minimum that many area retailers insist upon if customers want to pay with credit cards:

Mel Levinson of Lamps Unlimited contends that I missed the point in an earlier column that criticized imposition of the minimum. "The reason for the minimum is that banks which back credit cards charge merchants a percentage based on the average size of each sale," he said. "If I make a $100 sale, then several $2 sales in a row, my average goes down, and my charge goes up."

As a result, Levinson argues, it's actually a smart long-run move for the consumer not to use credit cards for purchases of less than $10. "If our charge goes up, we'll pass the cost through to the consumer, of course," he said. "So the consumer helps himself by helping us."

Jack Frank of The Button Shop notes that "the $2.50 credit card customer is the one we most often find on the fraudulent card list. We're better off without that kind of customer." And if you find an honest customer who wants to charge a small purchase, Jack says Frank's Law applies: "The less they want to charge, the more time they waste fumbling for the card."

From the customer's point of view, however, a $10 minimum can pose a hidden snag. Even if you need only one item, you may have to buy a second to reach the magic $10 level.

That's exactly what happened to Jane Bishop of Brandywine when her son was small -- and sick.

"I needed a vaporizer real bad and had no money at the time," she writes. "The vaporizer was eight dollars and I had to buy a two-dollar item I didn't need . . . Was I mad!"

Sometimes, however, stores will accept Visa when they won't accept checks. Marie Lankford of Woodbridge bumped into an especially strange variation on that theme not long ago.

Marie had moved to the area recently, and she tried to pay for $72 worth of drapes with a check drawn on a local bank. She furnished three IDs -- a Visa card, a military ID and a California driver's license. The clerk went to confer with the manager. When she returned, she made the bizarre announcement that Marie would have to allow her picture to be taken since the number of the check she presented was below 300.

Rather than go through that, Marie offered to pay with her Visa. It was accepted without a tremor -- even though Marie was the same person the store had implicitly accused of being untrustworthy 30 seconds earlier.

And if Visa ironies are your cup of tea, Susan Lawrence of Northwest has a beauty.

She went downtown to pay a bunch of back parking tickets with her Visa. Even though Visa International forbids minimums, the District government enforces one: for amounts of less than $10, only cash or a check will be accepted, according to a sign by the cashier's window spotted by Susan.