Really depends, if it is just a chassis, then quite probably not alot, if it comes with axles and drivetrain then its worth alot more. Does it have a V5?
The last chassis I sold was a used but good condition 1970's RRC for a tenner on Ebay.
Would be worth more to the right person, but seeing as I bought the whole car for just £300 then it wasn't too bad.
Regards
H