Unfortunately, abuse of the first sale doctrine is fairly rampant in the small-press bookselling world. This is a real sore spot with me, and is going to take some explaining, so get comfortable.
You have possibly encountered on-line booksellers who offer copies of books (often books they did not themselves publish) for outlandish prices. I myself have seen copies of my Cemetery Dance collection Things Left Behind going for as much as $1,750.00 (which, by the way, is a good deal more than I received for writing it; not bitching about what Rich Chizmar paid me for it, not at all, but I would dearly love to have more than one copy of my first book but that ain't gonna happen because I can't afford the prices many places are charging for it). The recent sold-out release of Borderlands 5 turned up at several on-line auctions within days of its publication with bids starting -- starting -- at between $200.00 and $500.00.
There are some who mistakenly think this sort of thing is illegal; it isn't. It is allowed under the first sale doctrine; whoever first purchases the physical copy of a copyrighted work (a book, a DVD, VHS tape, CD, etc.) has the right to do with that copy whatever they want, including transfer ownership of that physical copy in any manner they choose. They can give it away, sell it to some place like Half-Price Books, or offer it up for on-line auction. The First Sale Doctrine deals with the physical object, not the intellectual or artistic expression contained within.
Here's what pisses me off about this: there are some booksellers and individuals who will purchase and hoard multiple copies of a book with no concern for the work, the author, or the work's fans -- they couldn't give less of shit about the quality of the stories or the novel. What they're concerned with is obtaining as many physical copies as possible because (as was the case with Borderlands 5) a particular book might sell out very quickly, and they, in turn, can sell their copies at a price that is sometimes as much as 700% higher than what they paid for it originally.
When confronted with their unapolegetic avarice (and avarice it is, make no mistake about that), they will inevitably defend their actions by claiming that they've every right to turn a profit on their investment...and then probably have the nerve to bitch about having to pay two bucks a gallon for gas because OPEC are a bunch of greedy bastards. What's wrong with this picture?
Understand something: I am not condemning specialty-press publishers like, say, Donald Grant, who produce exquisite (and justifiably expensive) limited editions of books geared toward book collectors -- those rare birds who have a deep and abiding respect both for the physical object and the work contained within and who, it should go without saying, can afford these editions. Nor am I condemning any specialty-press publisher who at a later date offers up copies of a book they've previously published at a higher price: after all, it's their product, and if they can find a buyer for their product, more power to 'em.
I am also not condemning those who offer up for auction or re-sale books with the intent of using the money to assist others who are struggling with financial hardship (the upcoming auction to benefit Charles L. Grant being a prime example; I donated a book of mine and hope like crazy that the bids climb into the hundreds for it because Grant is a wonderful guy and superb writer and shouldn't be saddled with spirit-breaking worries over medical bills).
My problem lies with those who buy books solely for the purpose of re-selling them at obscenely inflated prices so as to fatten their personal pockets just because they can.
No, it isn't illegal, but in my book it is and always will be reprehensible and immoral. Which is why I do not buy books from sellers who engage in this practice, be they on-line or in the dealers' room at a con. As far as I'm concerned, it's price gouging if I see a book selling at more than twice its original asking price -- I'm not completely unreasonable about this; I realize that booksellers have to make a certain amount of profit to stay in business and cover basic operating costs, so doubling the price of a sold-out or out-of-print book strikes me as equitable and fair, but beyond that -- I walk away. And God help 'em if they have the nerve to ask me to sign any books for them so they can jack up the price even more.