I went to the bookstore yesterday to buy some books. I bought a book we had read exerpts of in my Chinese class at Swarthmore, a folk tale book, but my main purpose was to buy a a Ha-li Bwo-te book (known in some backwaters as "Harry Potter"). They had books 1-5 in Chinese (for those who don't know, there are currently 6 books in the series). The books have in general been increasing in length, with the first book around 300 pages and the 5th book over 800 pages. Chinese books are in general much more compact, but of course the 5th book was still almost three times as thick as the first one. The reason to mention this at all is because in China, you apparently pay for books by weight. The first book was around 20 kuai ($2.50), where as the last book was almost 60 kuai ($7.50), and each book in the middle increased its price in proportion to the increased length. Sure enough, I noticed my smallest book was the cheapest, and my largest thickest book was the most expensive.
I had noticed this phenomenon in another book store, when I went to buy a book that had been sitting under a sign that said 10 yuan. I had assumed that meant 10 kuai per book (yuan and kuai are both words for the RMB, the Chinese currency). Much to my surprise, when I brought the book up to the counter, the woman put it on a scale. It turns out that it was 10 kuai per 1/2 kilogram. The book, worked out to actually be 11.33 (spoiling my hopes that I had perfect change). I suppose the logic is that if the book is longer, there's more reading material in it, and hence it should be worth more money.