Unlike the UK or Finland, where the school textbooks are provided free of charge, in Spain one has to buy them; at least, most of them. And they ain’t cheap. For example, for his first year Bachillerato, Yuri needs six (6) books, each priced about €30 in the bookshop, except Historia del Mundo Contemporáneo which costs €42! You can save a few euros shopping at Amazon.es; unfortunately, they don’t offer free shipping for Canaries. Moreover, I found one of the textbooks sold slightly cheaper by a vendor via Amazon.es but there was no option to deliver to Canaries at all.
So I decided to explore the second-hand market. In Fuerteventura, there are no second-hand shops; at least, when we lived there, they did not exist. There are a few in Las Palmas, but I don’t know any specialised bookshops. However I was able to find all the books for Yuri at segundamano.es. (I used the same website a few months ago when I was looking for a house to rent.) I thought the most difficult part for me would be arranging meetings with the sellers: I hate phoning! It turned out to be a fun way of practicing my Spanish. To pick up one of the books, I had to take a bus to hitherto unknown (to me) part of Las Palmas, where I explored streets named Calle Polca and Calle Mazurca.
There is quite a diversity of school textbooks in Spain: you don’t just buy a math textbook for the 3º ESO, you need a specific one. And they tend to require the newer editions every year. Good news that some of Bachillerato books stayed the same for several years. I mean, there was not too much progress with Ancient Greek or Latin recently.
Finding the second-hand books for Timur was a bit more tricky. Luckily, I discovered Relibrea, an excellent web site dedicated to buying/selling of second-hand books. There was nothing available in Gran Canaria but eventually I found the sellers ready to send me the books from Madrid.
Result: of the lot (twelve textbooks altogether), the most expensive book did cost me €16 (plus postage), the cheapest €8; total saving at least €200.