Diamond pendants, calculators, home duplicating machines and luggage are just a few of the items that have been offered to me at "special prices." Photographs of these luxuries are usually printed on glistening, magazine-type paper and neatly enclosed with my monthly MasterCard, Visa and department-store bills.

"It's so simple," they say, "just fill out your credit card number in the blocks, indicate how many of each item you desire, and send it in."

Usually, there is a free trial offer, i.e. keep it for 30 days and return if not satisfied.

I welcome bills in my mailbox about as much as a swinging single welcomes herpes simplex II. At least herpes comes by itself. Bills come with enclosures.

As we slash the envelope open, out come shiny, neatly folded, sometimes perforated nuisances. Unfortunately, we are subliminally obligated to glance at them while in search of the primary contents.

Most of us go to our mailboxes each day hoping to find something pleasant--a letter from an old friend, money we once loaned being returned after a long time, or perhaps an invitation to a dinner party or a wedding. Inevitably, there will be bills, but to be tempted to spend more money than we already have is more than most of us can bear, and could even be considered the height of chutzpah.

I especially take umbrage with the offers featuring diamond pendants, emerald earrings and pearls. I find it unfortunate enough that I had to buy the mere necessities of life (underwear, cooking utensils, etc.) on credit. Why, oh why, are they tempting me with jewels?

I do have to admit that once, due to the enticement of the MasterCard people, I did send away for a calculator. In the meantime, a dear friend presented me with a calculator for Christmas, far superior to the one I had ordered. Taking advantage of the 30-day free trial offer, I sent it back as soon as it arrived and requested that my credit be adjusted. When my next bill came (accompanied by more glossy offers) the calculator was listed on the bill as though I had never returned it. It took some months and many phone calls to straighten it out.

Another time, my Sears bill arrived with an advertisement for satin sheets. Being newly remarried, I considered sending away for a set. After studying the color chart for about a week, I couldn't decide on a color. It was a toss-up between eggshell and mauve. I carried the color chart around for a while, and one day I searched my purse and couldn't find it.

Somehow my own absent-mindedness and lack of organization saved me from actually carrying out this frivolous act. The Sears bill was paid and I gave up wishing for satin sheets--forever, I hope.

All this leads me to wonder how the credit-card people decide on what type of items to plague us with each month. How do they plan this encroachment?

I picture a gentleman sitting behind a large conference table with all the advertising material on it and a map of the United States. His name could be Seymour Buymore.

"Let's see," says Mr. Buymore, "the Washington, D.C., area has lots of free-lance writers, let's hit them with the home-duplicating machine this month; and the people over here in Minneapolis, maybe they're going South to escape the cold weather, let's hit them with the luggage."

Actually, I have found a way of dealing with this unwanted literature. I simply close my eyes, hold the envelope high above the table and allow it to descend like tickertapes. Opening my eyes quickly, I spot the actual bill and quickly brush the other stuff off the table, into the trash.

This takes some time and a little eye-discipline, but after a while it becomes habit; and it does make you appreciate the junk mail that comes a la carte, the kind you can throw away, unopened.