I didn't buy the books, and am glad. I have it all on the IPAD, which is fine. I did buy Phil Croucher's ATPL book, which I find very handy if I want to "revisit something", or get another take/more detail on a specific area. It's a very handy size also, and I can imagine a great reference for the future interview, or when you need to remind yourself of something.
As for the study pack, I don't think you'll get it cheaper else where really, or if you do, it might only be a few quid.