If you're not careful, buying a stereo can be a lot like finding a mate: you can spend much time shopping around, take what looks best, and then, once home, discover you're stuck with a lemon.

Among students there are two kinds of buyers: those with three hundred dollars or less who just want to hear music and those with more money who demand high-fidelity sound.

If you're in the first group of casual listeners, then you will be easy to satisfy. The special combinations--package, amplifier, tuner, turntable and speakers--represent excellent buys. Clip out newspaper advertisements and then visit a few stores to see and listen. The turntable--usually a Garrard--and receivers will be decidedly mediocre. The real difference will be in the speakers. Don't go near any combination system with what look and sound like $20 speakers. Sound from a stereo can only be as good as the signal from the weakest component in the system; it's a waste of money to get decent sound through all those transistors and capacitors in the amplifier only to allow inferior speakers to mangle it. Also, ignore everything the brochures and salesmen tell you about these systems. At this price range the statistics are meaningless--shop around for an afternoon or two and buy whatever sounds best.

If you're an audiophile who is determined to spend your summer paycheck--$300 to $1500--on a complete component system, then shopping for a stereo can be a tormenting experience. The first thing to realize is that, unless you're a physics major, you know nothing about the electronic workings of the systems you look at. Advertisers and salesmen will come at you with "the 400-millisecond miracle," "reverberent field dominant," and "silver-lined circuitry." Don't worry if you don't understand these terms; you're not supposed to. The companies are preying upon your technical ignorance and attempting to dazzle you with impressive-sounding terms so you will trust their "expert" judgment of which product is best.

In an amplifier, power and distortion are the two most important qualities. A system that will be used for raucus parties needs power (your listeners will probably attribute the distortion to something else). The classical music listener needs low distortion. The primary technical problem in designing an amplifier is to permit the listener to increase the volume (power) without increasing the distortion. Generally, for a receiver up to $350, the buyer sacrifices one quality for the other, depending upon his preferences.

Before comparing two companies' products by their specifications, make sure the statistics have been measured in exactly the same manner. Often manufacturers attempt to make their models look better by publishing power and distortion ratings for inaudible decibel levels. The specifications for amplifiers that will make a difference to the ear as well as the oscilliscope are power in watts, continuous per channel at 8 ohms, and percentage total harmonic distortion (THD) at rated output. Ratings of 20 to 40 watts per channel and .5 per cent THD should be adequate for most Harvard rooms and listeners.

Before purchasing anything, however, you should obtain Stereo Review's annual Directory and Buying Guide, which contains summaries of features and specifications for all products, accompanied by helpful "how-to" articles. Then visit your local hi-fi dealers to listen to his equipment. Don't let your dealer demonstrate an inexpensive turntable by playing it through a $1000 Marantz amplifier and Bose speakers--insist he hook it up to other equipment in your price range.

No one need ever pay list price for any item and no shrewd buyer should pay the marked price on any equipment costing over $200. If the dealer is charging list price, look and listen, but don't buy. His profit margin is large enough to afford a few browsers. If the displayed price is already marked down, then the trick is to appear ready to buy a system or component, but unsure about what and from whom. After a half-hour of hesitation the salesman will either drop the price or throw you out. Some other techniques that work: seem dumb but price conscious. Again, after a while, he'll probably cut the price 10 per cent to give you "what you've got your heart set on." The most level-headed technique is to tell the salesman, "I like the Marantz 2040 but your next-door competitor is offering it for $25 less."

Don't feel guilty or timid about applying anything I've suggested. The stereo industry, through differentiation of product, is trying to exploit your ignorance about electronic equipment. No dealer is ever selling an item below cost and it's your right to get the lowest price.

Finally, be wary of new innovations until they are proven. Manufacturers are currently stuffing the market with the new quadrophonic systems. Stay away from these unless you have a large room and lots of money (at least $1000). The lower-priced models are still little more than conversation pieces.

If all this isn't disquieting enough, let me pass on what one dealer told me to bear in mind when considering spending a little more for a system. He said, "Look. You play anything five days a week five hours a day and it's going to give out after a year anyway, right?"