If you’re like me, you scour book auction and sales sites to find the best deals available in order to grow your collection in the most inexpensive way possible. However, while scouring, there is usually plenty of crap to sift through–namely ads proclaiming, most likely in ALL CAPS, that their item is RARE with a hefty price attached.
Situations like these beg the question, if it’s rare, is it also valuable? And, like many other topics when working with collectible items, the answer is muddy. Yes, SOME items that are rare ARE also valuable, like a first print of Bloomsbury's Harry Potter and the Chamber of Secrets. A first print of this book is rare in that there weren’t that many of them produced, AND they’re also valuable, selling around $750 and upward, unsigned (condition depending of course). But, it’s not as cut and dry as this–more on this below.
However, in the case of the US Harry Potter and the Chamber of Secrets first state, first print, this book is not all that rare (approx. 250,000 first prints produced), but has value (albeit not the hundreds of dollars that people would like to charge, but it sells well in the $60-$90 range), because it IS a first print in this great series and collectors of Harry Potter books like to own first prints. So, there is value even if it's not all that rare.
To make things murkier, even if a book is quite rare and once held a lot of value, if it’s readily found on eBay or other bookseller sites for a wide range of prices (with all books in similar condition), the overall perceived value of the book tends to decrease, because the book appears less rare than it really is. For a non-Harry Potter example, at the time of writing, there are at least 11 first print unsigned US Cormac McCarthy Blood Meridian books for sale ranging from $570 to $4,950. As there are 11 up for sale at varying prices, the rarity factor of this book is lessened simply because there are quite a few for sale with a $4380 gap! As things sit right now, these 11 books are all competing for the same buyers essentially, and as these same 11 books have been up for sale for awhile, the buyer is quite aware that:
1) they don’t have to “pull the trigger immediately” because, if they miss one book, there’s another one similarly priced (or lower!) to snag;
2) there is the hidden assumption that another Blood Meridian will be listed sometime soon and the buyer can be choosier over where they spend their money;
3) The buyer can choose to wait out the high prices of these books and see if a seller will either accept an offer OR will put their book on sale.
Essentially, while the Blood Meridian 1st edition, 1st print is quite rare and at one point sold quite high, the book's overall value is slowly decreasing (illustrated by the slow book sales -- 2 have sold in 3 months - one for $1,875 and the other for $750 -- and increasing market saturation) even though there are still many bibliophiles who collect the author's works.
This same issue is also plaguing Harry Potter and the Sorcerer’s Stone. It’s rare book, especially in Very Good or better condition (b/c of the intended age of the original readership), BUT because there are so many up for sale on auction sites (9 alone on eBay US right now ranging from $750 to $3680), the rarity is diminished, pushing down the overall selling price of the books (last one sold for about $750 January 1st).
Additionally, Sometimes books are so rare that they have no market value. For example: a Spanish audio book of Harry Potter y la Piedra Filosofal showed up for sale on eBay for $200, with the seller stating how rare the book was at every turn. Now, the seller is correct here; this Spanish audio book is quite rare -- not many were produced and there was only 1 printing. I know a few Harry Potter audio book collectors, but none are interested at this price point. They haven't seen one of these ever show up for sale and as such, don't have a way to gauge the value, making the purchase riskier. As a collector myself, I have found myself in similar situations, foregoing buying something that I know is rare simply because I cannot ascertain the value and as such cannot justify spending the money.
In short, I go back to the tenet that you should know the current market for the book you are wanting to buy as well as where you think this market is headed (especially if this is a long-term investment). Research what the book is selling for on auction sites (pay attention to sales trends over time, condition of the book, and anything else that might affect value over time to avoid over paying (and sometimes find a deal too). And whatever you do, don’t buy simply because the ad stated that the book is RARE.