The best website Ive found is
Gifts For Geeks Its a british based thing who has a MINIMUM of 25% off. They do hobby stuff as well and its just fantastic. I wanted to get some Krox but the site didnt have any so I emailed him and asked why and in 2 days there were Krox on sale at 25%off.
Since then I havent been to a GW store, I swear by it.