ONE DAY, back in the dark ages when I was growing up, my mother took me shopping for a blouse. We bought the blouse and then I got carried away. I decided I needed a skirt to go with it. To be precise, I needed the gray pleated skirt I'd just discovered on the rack. Back then, no teenager was complete without a gray pleated skirt. To my utter horror, my mother said no. She looked at me with that stern eye and announced firmly, "We can't afford it." I sulked, of course, and the story she told me about how she had been deprived of something as a child was no consolation whatever.

Don't get me wrong. We were not exactly what you'd call a welfare family. But this was back in the '50s when the standard model teen-ager was generally dressed by Sears and came equipped with a bike, roller skates, an alarm clock and one radio, which was reluctantly shared with several other siblings, one of whom might even be domiciled in the same bedroom.

That old-fashioned teen-ager found recreation at the movies or the roller-skating rink and played music on the living room stereo. Back in those days, that gray pleated skirt cost at least $8 and back then you could still do a lot with $8. Nowadays it won't even buy you a lift ticket.

Lift tickets have come into my life only recently and they have come there courtesy of the resident teen-ager who appears to have given up his ill-fated skateboarding career for -- what else? -- skiing. Now back when I was growing up, skiing was something rich people did. The rest of us waited around, hoping for snow, and then we went sledding.

That, of course, has all changed. It seems the entire teen-age segment of the population has taken to the slopes. High schools have organized ski clubs and commercial organizations set up ski tours specifically for teen-agers. Teen-agers from our neighborhood recently went to Canada for a weekend of skiing. Entire teen-age telephone conversations are devoted to the relative merits of various bindings. I know now that when our teen-ager suddenly starts talking about "150s" that he is discussing skis. The thing has gotten so serious, in fact, that he has been spotted on several occasions reading the classified ads of newspapers in what appears to be a serious pursuit of used ski equipment.

That, you should realize, is major progress. When he first decided to launch his skiing career he announced that he did not want his own stereo for Christmas. Instead, he wanted his own new skis. That seemed reasonable enough, until I discovered new skis don't cost $25 any more. In fact, $25 will hardly get you bindings. Then you still have to get skis, poles, and boots, not to mention waterproof pants, and a waterproof coat, and waterproof gloves, long underwear and ski goggles.

By this time you are in for a good $350 or more, and you've just started. There is also the matter of transportation, lodging, food and lift tickets, all of which can set you back $100 or more for your simple weekend on the slopes.

And there seems to be no end of weekends on the slopes. Things have gotten to such a state that my husband reacted to the latest skiing invitation by standing up in the living room and announcing loudly that we were not the Rockefellers. And I, trying to keep peace in the family, found myself saying soothingly, "Of course not, dear. We all know that."

Things might not be so bad if skiing were the only thing teen-agers wanted to do. But of course it isn't. They also want to go ice skating on Friday nights and the movies Saturday nights, with an occasional $25 rock concert thrown in. Their idea of an after-school snack is a $5 munchout at McDonald's.

And there seems to be no end to the equipment teen-agers need simply to get by. No teen-ager is complete these days without his very own blow dryer, as well as his own clock radio, stereo, camera, television, telephone, ice skates, skateboard, roller skates, bicycle and, of course, skis, poles, boots and the rest of it, all of which he keeps in his very own private room with attached bath.

A friend who is the father of three teen-agers and who therefore can be forgiven a certain hysteria about these matters blames the whole thing on Madison Avenue. He says Madison Avenue is breaking up the American family. Each member of the family has been convinced he has to have his own television in his own room, for example. So they all stay in their own fully equipped rooms instead of coming out into communal areas such as the living room and having a good old-fashioned argument about whose records are going to get played on the family stereo.

I know of another family in which the parents took desperate measures to stay afloat in the sea of designer jeans and Italian sneakers. The father said he would contribute the Sears cost for a comparable item and the teen-agers could make up the difference out of their own funds.

I've thought of another way of coping with teen-agers you can no longer afford. You can take out classified ads that would read something like this: "Teen-ager: pleasant, helpful around the house, good with younger children, needs home. Affluent families only need apply."

That's a fantasy, of course, and having fantasies is no way to solve the various issues that come up in child rearing. Having fantasies is a way of ducking the problems.

So I'm going to stop having fantasies and I'm going to take the bull by the horns this time and I'm going to sit down and have a meaningful discussion with him about this whole problem, and we're going to get this settled once and for all.

I'm going to tell him about the gray pleated skirt.