I have a 1/18 replica, at one point it was worth almost a grand (I paid $130 for it). But, it was a limited run of Dan Gurney's winning Cobra Daytona Coupe, and the limited run of that model drove the market up. When I went to sell it though, the market had tanked thanks to the sub-prime silliness that ultimately cost me my job, early market failures, bailouts, etc. Last I saw I might get - before fees etc. - maybe $250 for it.
OTOH, that was a few years ago - I should look again . . . . .