THE HOTTEST THING in the fashion business today, the clincher in every purchase, has nothing to do with color and silhouette, and no designer can take credit for dreaming it up. It is seasonless and suits every figure and every budget.

The most irresistible thing on the racks today? A pricetag marked "sale".

It is the clearest sign that things are not going well in the fashion business, that buying fashion when it is fresh in the stores at full price is, well, out of fashion. Stores are offering clothes by manufacturers and designers that many customers have rejected as overpriced, unattractive, poorly made, untimely, boring or just unnecessary additions to their wardrobes. At the first markdown price they are more appealing though a second slash in price boosts the chances of a sale still more.

In fact, things are now on sale so frequently that many men and women now simply refuse to pay full price for anything. Stores have taught us that every fashion has its markdown day. And they have conditioned the potential customer to wait for the sale that happens just about the time the weather catches up with the retail fashion cycle. Bathing suits are on sale right now -- in fact about the only thing not on sale are some winter coats. (In a few stores those have arrived with special promotional price tags, too.)

Consumers have begun to react angrily to price tags that they consider out of touch with the worthiness of the clothes. They find it hard to understand why a silk blouse is worth $240, or why it is difficult to find quality leather shoes under $100.

The cotton blouse with a price tag of $120 looks like it is worth about $40. It is simply cut, it is unadorned, undistinguished in quality, the fabric is plain and it doesn't seem to have any special design in it, at least on the hanger. As a matter of fact, it probably is worth about $40 in fabric and labor. But then tag on a profit for the manufacturer, and a bit more for the designer, double the price and a bit more for the store to pay its cost of doing business plus a small profit, and the total is easily $120. It still looks worth about $40.

And with clothes marked down by one-third or one-half (and now an additional 20 percent discount added on top of that in some stores), customers have started to ask questions: If an item can be put on sale for so much less than the original price, wasn't the original price way too high? (And one has to worry that stores may decide to price things higher still knowing that they have to put things on sale to get customers to buy them.)

Buying things at lower than list price in off-price and discount stores has been going on for years. But now, rather than being embarrassed to admit that an item was purchased from a discounter or from a sale rack, cust brag about the money saved, quoting specific prices gleefully, as though they have retaliated against a conspiracy for high prices.

Constant sales have become a way of doing business as stores have been stuck with huge inventories in the past two years. Some prestige specialty chains that used to dump much of their sale merchandise through discounters have started selling the markdowns themselves as a way of luring customers into their stores. Other stores have set up special sections of the store as sale areas where sale merchandise can always be found.

Designers and manufacturers have responded to the change in buying patterns by making their offerings more conservative, more "safe." Rather than gambling on fresh looks and innovative styling, in many instances the new line of the season is now a slight variation of the best sellers of the season before. For example, jackets shown for fall were often just fractionally shorter than those offered last season, the shoulders just a bit wider -- or narrower.

But to customers who were finding the price tags gargantuan, such slim differences didn't seem worth buying something new. Why replace a perfectly good blazer for one a tad more fitted and just a tiny bit shorter with a price tag of $280, or more? The one in the closet will do just fine, thank you.

The fashion business is feeling the impact of the 1970s attitude that anything goes and one should wear what suits best. Designer edicts are pass,e. But as a result, many women go into stores, select a jacket from one rack, a sweater and skirt from other racks and try them on.

Standing in front of a a mirror the customer asks herself, "Well I've chosen my own look but do I like it?" The conclusion is often, "I don't really know." And with little skilled help around to assist in such a choice, the sale is often forfeited since she can't decide if she likes the new items so much better than what she already owns.

Many of the new clothes are so limp and formless on the rack that it takes a lot of wooing to show a customer how the style should be worn and why it is worth the price tag. Stores with many branches find it increasingly difficult to find, train and maintain skilled personnel in each store for the long hours that stores are open. (Some mall stores are open seven days and several nights each week.)

Sometimes it is nearly impossible to find any sales person at all to ring up a sale. With so few salespeople, stores have found it essential to wire and lock expensive garments such as suede jackets to curb shoplifting. The shoplifter can't get at those choice items, but neither can the customer who might want to try them on.

Over the last year stores have increasingly banked on private label programs as an attempt to keep down prices and vary the merchandise in the stores. Usually manufactured offshore, often in the Far East, stores bypass designers and become the manufacturers themselves, having things created to their specification. Theoretically it should make these clothes, usually marked "made expressly for (and the store name)," sell for less since the store is both the manufacturer and the seller and the item has one less mark-up.

But often it's quite the opposite. Many stores have found private labels a way to make extra-large profits. Since these items do not have manufacturers' names in them so the customer can make price comparisons between stores, stores are using these items to make an extra profit, rather than pass the price advantage along to the consumer.

There's a certain irony in the big price tag's teaching us to be more careful shoppers, to appreciate well- made clothing that endures in both style and workmanship. And it has revived some of the old values, often considered European, in taking care of clothes -- hanging them up properly, spot cleaning, hand washing, brushing and dry cleaning less frequently.

It is also encouraging men and women to get more use out of their clothes, buy fewer things and wear them more frequently. It has boosted the appeal of accessories, strong splashes of fashion at a price. A big price, but it is far less than the price of a new shirt, for example.

The best news is that designers and retailers know they have a serious problem and are talking about it. They are hurting where it hurts the most -- at the cash register -- and they know they must make some changes. The stores have asked designers to "stop prostituting themselves, putting their names on everything," and get back to the business of designing clothes. The designers have asked stores to get out of the promotional-price business, "to get back to the basics of being good retailers, offering lots of fresh items to customers at the time they want them."

If it really happens, buying fashion could become fashionable again.