Poundland have taken delivery of both Jenson Button and Lewis Hamilton's books, both in Hardback. This deal was seen in Swansea, but it applies nationwide aparently (subject to stock availability!). The next cheapest price I saw these going for was around the £4-6 in the works some 6 months ago.
Jenson Button's book has a RRP of £20.00 on the back and is an in depth account of his championship year with Brawn GP in 2009 and It even has a foreward from Ross Brawn himself. the book Includes an Introduction on the whole Honda pulling out-Williams sigining- Brawn buying out saga, along with a pretty detailed race by race account for the whole season which includes a testing, a qualifying, a race and post race report along with some pretty good photos There are better reviews on amazon if your interested to find out more.
Hamilton's book is the "special celebration edition" which again has an RRP of £20. more of a short autobiography with an emphasis on his 2008 World championship season. It also has a few nice pictures and again, if your intersted there are better reviews on amazon