Lonely Planet currently have a 3 for 2 offer on. Buy any 3 books over 9.99 each and you get the cheapest free.
There is a 20% off voucher that has been around a while, which I went to use, but to my surprise the 20% came off the original total, not including the 3rd book free.
Then on top of that there is 20% Quidco, making this a real steel if you're going travelling and want 3 of their travel books.
3 Books @ £15.99 = £47.97
- 20% (£9.59) = £38.38
- 1 Free (£15.99) = £22.39
- Quidco (£4.48) = £17.91
Total 17.91 for 3 Travel Books
There is actually a better 40% off voucher that you can use - HAYSTACK40 that brings the total down to £12.78!!!