At this season, we are preoccupied with buying and selling, so you might be interested in two phone calls I received recently.

Both calls were from indignant men. The first told me that on a Tuesday he had purchased an electronic toy for $30 from Store A, but on Wednesday he had been astonished to see precisely the same toy advertised by Store B for $50.

"This is unconscionalbe," he said in an angry voice."They are gouging the public. They are charging 60 percent more for the same identical toy. They should be denounced."

I was almost tempted to tell him that 50 is 66.6 percent more than 30, but I realized that would only make him more indignant.

So I played it straight and said, "Sir, you must remember that we're dealing with a free marketplace where all sorts of things can happen. One store may offer a limited selection on a cash-and-carry basis while the other store carries a big inventory, delivers and extends credit. What's more, one firm may use an electronic toy as an advertised special designed to bring customers into its store while another firm uses coffeepots or electronic scrub boards as its advertised special. You have to shop the ads carefully to see who's lower on the items in which you're interested."

"My dear fellow," he said, "it appears that I have not made myself clear to you. Store B is cheating the public. It is charging 60 percent more than Store A."

"Sir," I replied, "I understand your point, but perhaps you don't understand mine. I'm saying that most stores charge the regular list price on some items and offer discounts on others -- but in a free marketplace stores discount different items. A store may be lower on one item and higher on another."

"Sixty percent higher?" he asked scornfully.

"Look at it this way," I said. "Instead of being indignant that Store B's price is abnormally high, why not praise Store A for offering an abnormally low price?"

"You just don't understand," he said as he hung up. And he may be entirely right about that.

The other indignant man began with a preamble that I felt sure would lead me into a trap. He said, "We're all supposed to save gasoline these days, right?"

"Right," I said, thinking of the $25 I had just paid for a fill-up.

"So what does a sensible person do before he goes out to buy an item?" He answered his own question. "A sensible person gets on the phone and asks whether the store has the item in stock. But if you try it, you'll find they won't tell you. They're too busy waiting on customers. They tell you that at this time of the year they can't answer questions about what's in stock. You have to come to the store to find out whether they have it or don't."

Who gave him such an answer? He said, "Don't take my word for it. Just call any of the catalogue stores."

The first one I tried, at random, was Best Products. I relayed the complaint to store manager Charles Beach and asked for comment. "Did your reader say he got that kind of response from our store?" he asked. "I would find that hard to believe because we have a system that is designed to avoid that kind of response. The clerk who answers the phone probably doesn't know whether we have your particular item in stock, but we have a procedure through which the clerk can find out and then call you back with the information. If any of my people told a potential customer that we're to busy to tell him whether we have a certain item in stock, he or she was not following instructions."

For good measure, I tried Evans Distributors, where store manager Dan Palmisano told me, "Yes, it is true that at this time of the year we don't attempt to tell a person by phone whether we have a certain item in stock. If we look in our stock status book and see that we have five items on hand and we tell him that, it would be inadequate information because by the time the customer got here we might have sold all five. Then he'd be angry because we said we had it and after he drove all the way over here, we didn't have it."

Well, as I said, it's a free marketplace, and if you take the trouble to think about the forces at work in it, you can understand why buyers and sellers do what they do -- even if they don't agree with each other and you don't agree with any of them.