Autumn is the season when leaves fall and wine prices follow. If you've been wanting to start your own wine cellar, now is a good time to do it. The ideal small cellar contains some wines ready for drinking, others that will soon be ready and still others that require a few years of maturing. The aspiring hoarder should start with at least a dozen cases, a decent beginning but hardly a spectacular one.

Be forewarned that such a wine collection requires some ongoing attention. You will be regularly depleting a limited reserve, and a single dinner party can make a real dent in your stash. Therefore you will need to shop and replenish, and keep an eye on your vintner's shelves for what is good and economical. That is part of the fun.

Most of the wines recommended below are easy to find, affordable and thoroughly presentable. The prices listed are approximate; many of the wines can probably be bought for less. If you can't find the specific recommendations made here, there are many wines in the same price range that could be substituted. Ask your vintner for advice.

The real decision, of course, is just how much to spend. The possibilities are nearly infinite, so let's assume that $15 a bottle is max and half that amount preferable. We'll start with the keepers -- all reds -- and work back toward present drinkability.

First, a case of good, well-priced California cabernet that will start to come around in a couple of years. There are many fine ones of medium brawn at attractive prices, including the '82 William Hill Gold Label and the '82 Inglenook Limited Cask, each available for about $160 a case.

You'll also want a case of bordeaux that will show maturity fairly soon. The '81 vintage in Bordeaux was excellent, and if you shop around you can still find bottles for $15 or less -- including cha~teaux Talbot, Calon-Se'gur, Le'oville-Poyferre', La Lagune and others -- that were bought before the dollar's collapse. Count on spending about $180 per case, single selection or mixed.

For an imminently drinkable red with some age, buy a case of Cune's '73 Vinåa Real Gran Riserva, a Rioja, for about $140 per case. It will suit the most elegant dinner party.

For inexpensive cabernet that can be drunk now, buy Hawk Crest, from Napa, or Chile's Concha y Toro Marques de Casa Concha, each about $80 per case.

Get a case of chianti classico -- one of the best wines for the money and an investment that you can drink now or keep for several years. The '85 Podere Il Palazzino costs about $90 per case, and there are several others as good for that price.

Next comes the problematic pinot noir. Once you could buy a few cases of good burgundy to shove up against your cellar wall and you didn't have to worry too much about insolvency. No more. Better buy a mixed case of Saintsbury: Six bottles of its Carneros pinot at about $12 and six of its lighter Garnet at about $8 comes to $120 for the case.

Now for the whites. Chardonnay is the most popular and the most difficult, there being so many choices. Try the '85 Burgess Cellars for about $120 per case, or the '85 Sonoma-Cutrer for a bit more. You will also need a case of less expensive chardonnay -- Estancia and the new Hunter Ashby are both good and cost only $75 per case. Drink your less expensive chardonnay now and keep the other for a year or so.

Next comes sauvignon blanc. The Robert Mondavi Winery has returned to a lean, elegant fume' blanc. The '85 costs about $100 per case. Also buy a case of Lindemans semillon, from Australia, for $70.

Now for the Alsace wines, which are always well made and are suitable for drinking now or later: Buy four bottles each of Rene' Schmidt '85 riesling, Trimbach's '85 gewu rztraminer and the '85 Josmeyer pinot blanc. Figuring about $8 a bottle for the first two and about $6 for the last, that should run you about $88 for the case.

The last case will be composed of sparklers and after-dinner wines. You will need half a dozen sparklers. Champagne doesn't fit within the budget limits set here, so buy Domaine Chandon instead, at less than $12 per bottle. Get three bottles of drinkable port -- Sandeman's Founder's Reserve, or Fonseca Bin '27, for $12 a bottle. And, finally, a bottle of the '83 La Tour Blanche -- a light sauterne -- for about $15 and two bottles of Corbans '81 late harvest riesling, from New Zealand, for a mere $6 a bottle. This case: $135.

You have spent about $1,400, tax included. Chances are, you'll be back in the wine shop within a week. ::