Don't know if anyone else has noticed but a number of the Food and Drink books in the 3for2 offer are also part of an old 50% off offer which means you get 3 for 2 on the full price plus another 50% off.
e.g. three books at £7.50 = £22.50 - £7.50 (free book) - £11.25 (half price) = £3.75
There are quite a few books in this offer:
e.g. The Organic Seasonal Cookbook, How To Break An Egg Book, Easy Pies, most of the £3.75 books, etc.
Just click on a book and it tells you the offers applicable to it.