Depends obviously on the condition, but in my (limited) experience they are rare but sturdy cars.
Current ebay end-of-auction listings have seen them go between £200-300. Some of these auctions started at £0.01 and no reserve.
The Works editions (91,92,93 and 95) seem to go for more. If yours has various hop-ups (some of which are rare), then it may even go further.
I think the yz10 series are awesome and look so aggressive!
Don't sell yours...though some actual pics would be nice