If you know a fan of Lego or Star Wars (or preferably both) then this Lego Star Wars Stormtrooper Watch is a bit of a bargain. Lego watches have an RRP of £19.99, and although you can usually get one of these for around £15 or so John Lewis have them for £9.99, and Amazon are price matching.
It has interchangeable links so you can 'build' it, and it also comes with a matching Stormtrooper Minifigure. It also happens to be water resistant to 50 meters, but I can't imagine this is a feature that is on the 'must have' list for a child's watch
The watch is a children's one, so don't get it for any grown up fans you might know as it won't fit them, and from some of the Amazon reviews it sounds like some adults have been a little disappointed by this.
If you order from John Lewis you can click and collect for free from them or from Waitrose, or home delivery is from £3. If you order from Amazon then delivery is free for Prime members, otherwise charges are from £3.49.