Here in the United States, it became more common for students to purchase their books, usually through a college bookstore; at the end of the term these could be sold back for some portion of the original cost. This could be thought of, of course, as rental by another name -- the difference between the original cost and the buyback amount being the 'rent' -- but at least it gave students something tangible, something they could even (if they wished to) keep. Publishing college texts was an unglamorous business, and in the humanities at least college texts tended to be plain, durable, and drab.
Then came the publishing-merger boom of the 1990's. As other kinds of sales became less predictable, the idea of a captive audience of students who would have to buy a book became a vital asset, and textbook publishers consolidated even more than trade publishers. In the end, just a few giant publishers -- Pearson being the largest -- ended up controlling most of the market (the list of publishers gobbled up by Pearson is a who's who of the old textbook universe: Scott Foresman, Penguin, Longman, Allyn & Bacon, Addison Wesley, and many more). Controlling as much of the market as it did, Pearson could set its prices as high as it liked -- by one account, textbook prices in the past 20 years have gone up 812%.
What was a student to do? One could try to find a used copy, and until a few years ago the friendly folks at Off Campus Books would often have one available for 20% or 30% less; when buyback time came, they'd also pay a bit more. Many college towns had such stores. But publishing giants like Pearson didn't like this secondary market, and went to extraordinary lengths to undercut it: they issued "new" editions constantly (which had the effect of making the old ones worthless) even when all they'd done was change the page numbers; they included online material with an access code that would be useless for anyone but the original purchaser; they bundled Blackboard support with books in a similar way, so that the book itself would be insufficient. And their strategy worked; Off Campus Books went out of business, as did many similar stores.
French or Spanish texts for $150? Science textbooks for $250? Business textbooks for $450? When a book with the same number of pages and binding sells in the trade-books world for no more than $40? And that's only the half of it; some of the same publishers also market reference books to libraries (another seemingly captive market) for as much as $1,000 a volume.
Who can afford such books? Almost no one. And so, textbook rental has come back, with a vengeance. Amazon, Barnes & Noble, and other online services offer them, and many college bookstores have arrangements with book publishers that allow for rental of a physical book through the store's own system. But beware: often, the rental price is not all that much lower than the cover price (and surely more than a used copy would be) -- and, if you forget to return your book on time, your bank account may be dinged for the full retail cost of the book PLUS late fees. And, even if you DO return the book, it's possible that Amazon (or whoever else it may be) will decide that it's "no longer in acceptable rental condition." If that's the case, they charge you the full price, and send the book back to you.
You'd think that, in the same age where Netflix and other no-late-fee subscription services put Blockbuster and Hollywood Video out of business, that high initial costs and huge late fees would be a terrible business model. But students are a captive audience, and many of them don't read the fine print when they sign up to "rent" a book and save a few dollars. Some students have lobbied for regulating textbook prices, and in response, there's now a Federal regulation -- but it doesn't limit book prices. It just mandates that professors announce their textbooks farther in advance, giving students "time" to search for better bargains. Good luck with that.