1Skip the impatient, condescending store clerk, and simply look for the least expensive edition of the piece. You can often find great reissues by established conductors and symphonies for just seven or eight dollars, and random chance can be a rewarding way to build your collection.
You'll occasionally see what you're looking for brand new and sealed, for just two or three dollars. That's usually a tipoff that the recording is not very good; the distributor is stuck with too many copies, and they're not selling.
A good rule of thumb is to stay away from any CD that doesn't mention the conductor and/or performers on the front or back cover. If you have to open it to find out who contributed, it probably isn't very good. These are usually found in the under-$5 category.
I discovered this with a recent Mendelssohn purchase on eBay. My winning bid was a penny, and shipping & handling was just $2.00 (this was a new, sealed CD). Of course, neither the conductor nor the orchestra were listed on the CD cover (or in the eBay ad). The reason so many copies of this recording are available at such a low price: poor sound quality. The performance was fine, but something went wrong in the recording or engineering process, and the result was the same as if I had placed my speakers in a cardboard box.
To put it clumsily, you don't always get what you pay for (i.e., great finds can be had for only about $7-10), but you always don't get what your don't pay for (meaning, save your three dollars toward a CD that lists the composer on its cover).
2Speaking of eBay, it's a great way to build your collection, along with Amazon. Both sites offer new and used CDs, and if you don't mind buying used CDs, you can find all sorts of masterpieces for just a few dollars. Even if your collection has to be pristine, you'll often find what you're looking for more easily, and at a lower cost, than you will at even a large store like Borders. Again, random chance can be fun.
3Check the reviews at classical.net, then order the version that appeals to you (through eBay, Amazon, Borders, etc.). This site reviews several versions of almost every piece you can think of, and will often steer you away from an inadequate recording.
http://www.classical.net/music/recs/reviewsThe reviews also offer opportunities to rediscover music you already know. I love my copy of Shostakovich's Symphony No. 15, and now have on my wish list a version I found at classical.net which is done in the style of chamber music. I wouldn't have found that by browsing the online or retail stores.
4I mentioned random chance twice. The beauty is that it leads to educated choices. Only you can decide if Bruno Walter is a better conductor than Daniel Barenboim, because it's all subjective to your personal tastes. Listen to enough classical recordings, and you'll soon know which conductors and performers are the safest bets.
One of my greatest pleasures in this hobby is owning more than one version of a piece, and comparing them. I like the clarinet in Tamas Vasary's recording of the third movement of Schumann's second symphony
because it sounds thinner than in Rafael Kubelik's, which is the very reason someone else might have for hating it.
The clarinet in Kubelik's recording, however, reminds me very much of a Mozart concerto, which is enjoyable in its own way. I've never discarded a recording simply because I found one that was better; the truth is, different parts of a recording are better for different reasons, and when contrasting two or more, the result is usually a toss-up.
0This one is number 0 because it's what
not to do:
Don't fall in love with a library recording, then spend the rest of your life searching for that exact version to add to your collection (like I've done). When it comes to classical music, the library is already the epitome of random choice, so long term, you're better off just buying a random recording, and falling in love with that one instead.