what do you think

A 2 stroke will lose compression over time, (as will any engine). Ask him what was "rebuilt" and why, if he was still running the oil injection or pre-mixing his fuel. Blaster engines don't have to be beat on to need to be rebuilt, they can wear out from normal use, but the better you maintain your engine, the longer it will last, and most people don't know the proper way to maintain them. From the picture it doesn't look that bad, but look at everything else too, i.e chain, sprockets, brakes, FRAME, wiring, wheels, ect, ect, & it never hurts to feel the guy out & offer him less for it. :D
 
that actually looks pretty clean for an '01, worth $1000 ?????
only if he has reciepts for the top end rebuild, or the compression tests to at least 120 psi, and tires/brakes/chain-sprockets are all in good shape
i'd offer him $800 and see what happens