Worthy of mention that a cheap logbook costs maybe £6, and a very expensive one maybe £20 (okay there are a few exotic ones that cost rather more, but they are few and far between).
If you are planning / intending / hoping to do a lot of flying, then buy something reasonably large, robust, and good looking - you'll be living with that book for a long time, and the cost is trivial compared to virtually anything you'll ever spend on flying.
G