I use a brand of books called Teach Yourself, and they sell a Complete Mandarin Chinese Book/CD pack. You can preview it from that page. I haven't used it myself, but in September I plan on enrolling on a part time Mandarin class on an evening and I'll probably be using it then. I think Teach Yourself are good as a way of introducing someone to the basics of the language, but it depends on how you learn. Some people learn best by reading through grammar books and learning all the verb and tense endings, whereas others prefer to learn it in context. I would probably say Teach Yourself does both. For £20 I am not sure you have too much to lose.