One of the most important things to remember when collecting 45s is that 45 record values are directly proportional to their grade. Grading 45 records (or any records, for that matter) is a difficult, necessarily somewhat subjective task. Unfortunately, there is no single good, easy to use grading system for records as there is for other collectables — comic books, for example. The most widely used grading system today is one put together many years ago by Goldmine magazine, which specializes in the record collecting hobby. Both eBay and Discogs have adopted the system, but sadly the Goldmine gradine guidelines are not well thought out, are hard to use, and cause more confusion for customers than necessary. At Classic 45s, we initiated a hopefully improved system 15 years ago, and that system has evolved continuously over time.
The Classic 45s system assumes that collectors are seeking 45s as close to Mint as possible, and we define "Mint" the way the dictionary does: "New, like new." We also adopt the comic book guidelines' definition of "Mint," as in "Nearly perfect in every way." This is a major difference from the Goldmine system, which — for some reason lost to history now — defines "Mint" as "Absolutely perfect in every way." With such a definition, no record can be rightfully graded "Mint," since nothing is "absolutely perfect." The Classic 45s system uses "Mint" to help guide customers to records that are either "New, like new" or "nearly perfect in every way," since that, I believe, is what collectors are seeking.
Another problem with the Goldmine system is that it uses a single grade for the entire record, not accounting for 45s that may have perfect labels but lousy sound, 45s with written-on labels but Mint sound, or 45s with scuffed-up vinyl yet play Near Mint. To solve this, the Classic 45s system uses four grades for each record: One for the label, one for the vinyl, one for the audio, and one for the record overall. This gives customers a much clearer picture of the record, which is important since at an online store you cannot examine the record in person.
When you shop at antique stores or most record shops, the 45s show no grade at all, and you are left to "guess" at the overall condition by its appearance attributes. In such cases, if possible, ask the store if you can play the record to determine audio quality. To this end, you may find carrying a portable turntable a good idea when you shop at brick-and-morter stores. For even though a record may look brand new, it may have audio playback problems that are not apparent. This is especially true for "styrene" (polystyrene) 45s, which are actually quieter than vinyl when brand new but which are more fragile than vinyl 45s and easily damaged with poor playback equipment. One key indicator for styrene records is that they have glued-on paper labels, as opposed to vinyl records, which have the labels "pressed" or directly printed on them. Don't avoid styrene (well, you can't, since almost all 45s made by certain companies — Columbia and Epic, for example — were styrene), but be cautious when purchasing styrene 45s if you can't ascertain the audio quality.
Also keep in mind that if you are primarily interested in the audio quality of a 45 record, don't be put off by scuffed-up vinyl or damaged labels. Vinyl 45s (some companies used vinyl exclusively — Capitol Records, for example) can look lousy but still sound great. This is why you should always listen to your old Beatles or Beach Boys 45s before tossing them, since even if they've been abused they may retain highly listenable audio.
The bottom line is that you need to understand the grading system that's been used wherever you shop. Find out if the dealer "play grades" their 45s or if they grade by appearance alone. Unfortunately, in my experience, the number of dealers who grade the audio as well as the appearance of 45 records is a small minority. So be cautious if great sound is your main goal.
That said, one of the reasons the Classic 45s system uses 4 grades is that some collectors are primarily interested in the appearance of the label or the vinyl (or styrene), rather than the audio. Collectors whose primary goal motivation is appearance have it a bit easier than those primarily seeking the best possible audio, but once again be aware that very few dealers grade labels or vinyl separately from audio, so a record's overall grade may be misleading, especially if the dealer is using the Goldmine grading system.
A word about warps: Many collectors new to the 45 record hobby think warps are a reason to reject a given 45 out of hand. Let me weigh in to say that most 45s are warped to one degree or another, and you'll drive yourself crazy chasing after that perfectly flat 45. In my experience, most kinds of warps that you find on 45s do not affect the playback or audio, assuming your tonearm is weighted properly. There are, of course, exceptions, and you don't want a 45 whose warp causes the needle to jump or skip a track. But mild warps, which cause the 45 to spin with a bit of a "wave", or "bowl" warps, which cause the center of the 45 to "bowl" out, are not troublesome and should not be feared. It is perfectly possible for such a mildly warped 45 to have pristine Mint audio, and that should trump your desire for a perfectly flat platter. Further, there are many "home remedies" for flattening vinyl records, and you can try one of these if a given warp really troubles you visually. Just take care that you don't damage pristine sound through flattening. Of more concern to collectors are 45s that are pressed slightly off-center, causing a "wow" in the audio. Such mis-pressings should usually be avoided unless you're just filling a hole in your collection until a better copy comes along.
Bottom line: If you want great audio, you can't judge by appearance alone. If you don't have a portable turntable or any other way to judge audio, avoid 45s with stickers, writing, tears, or other damage to the labels, as such blemishes greatly reduce the record's value regardless of its sound. Also avoid 45s that appear to have scratches, serious warps, or other problems with the wax (vinyl or styrene), as this usually indicates a problem with the audio. Buy the best-looking 45s you can find, but be prepared to pick up a "filler" copy of a rare title in hopes of finding a better copy some day. And please keep a lookout for that rare record that appears to be in VG condition but which may be a treasure in disguise: I paid $1 for a fairly beat-up looking copy of a single recently that turned out to sound better than it looked, and more importantly, turned out to be worth well over $2,000 even in that condition. The key here was that I intrigued by the small Detroit label from the 1960s, a reason why label collecting is a useful strategy.
A note on pricing: Determining the price of a 45 is directly related to its grade. If a record has a book value of $50, that typically means a Near Mint copy. Truly Mint records commmand a premium above book values, whereas 45s in lesser condition get priced lower than book according to their grade. The $50 Near Mint record will be worth only half that much if it's in "EX" condition and only a quarter of that price in "VG" condition. By contrast, that same record in Mint condition will be worth $55-60.