I tend not to buy the real stuff anymore, I get the clones from a site called marstoy.com and yourwobb.com
near perfect clones, not boxed but come with the full book instructions, Ive bought loads from them, last 2 were the DeLorean (built and looks amazing) and the Pac-Man arcade that Ill start in the new year.
I did buy the house from "Up" the other week cos it was down to 30 quid in B&M which was alright.