Aldi will have these rotating solar system lights instore from Sunday 08/12/13 for £19.99 which seems pretty reasonable.
Product Information :-
If your kids love outer space they'll love this.
Includes booklet about the solar system
Easily mounted to ceiling
Remote control operated
3 x AA/2 x AAA batteries included
Size: 17 x 8.5 x 8.5cm