I bought a copy of Vocabulary Expander from an Oxfam bookshop. I think it was the one in Oxford, along Turl Street. It cost me £2.49, and is in fine condition. Even though it provides excercises to expand one's vocabulary, I don't really do them; I use the book only to look at and see new words, though I have done a few of the "Odd Man Out" excercises.

Here is an example: carbon copy, software, hard drive, keystroke.