Up to 25% off Children’s Books at Waterstones! October 26, 2016 admin Gifts, Holidays, Home and Garden, Retail and Shopping Great News! Waterstones has a great customer offer, up to 25% off children’s books. Books range in age categories Pre-School, 5-8, 9-12 and Teenager. Great books like Diary of a Wimpy Kid Book 1 can be found in this selection. Up to 25% Off!