Do what jackson409 said and then make your own assumtions from there.
Any time you buy a used bike, especially one that has been used as you described you need to put some $$ into it to get it up to par. It will treat you right if you treat it right. Its a 99, mines a 01 RM250. I am envy of all the users that have real new bikes but I trust my bike to take me anywhere I need it go and its way paid for. I say go for it if you got the bug 
amenI'm pulling the trigger then! $750 plus....say $300 is still less than $1500 for ride ready.
post some pics of that sexy bitch once you get her. BUT watch out for M33, he has a serious Hard on for Yellow bikes.
although I can't blame him, they are the best bikes ever made bar none 
What year is it?Never fear! I have another craigslist find! RM125Y! $1000! Ride ready! Meeting him tomorrow night to check it out. However, I will take a look at bikefinds.com.