Read this forum daily so you can learn about the bike. You might think your getting a deal but its real easy to get bit in the ass on these bikes. Parts are not easy to come by so many of these bikes don't get the service they need.
Decide what you want and how you will use it. A mint condition all origional or perfectly restored bike is rare and will cost you more. You may want a driver your not afraid to get hurt which will cost less. Somebody recently mentioned that the bodywork determines the value. Unpaintded/unrepaired bodywork is worth more than fiberglass or aftermarket, but if your going to track the bike then you probably won't want OEM bodywork. Original Rothmans bodywork is worth $1,000 more, but its rare and often duplicated. I can't even remember ever seeing an original Rothmans for sale (they have all been fakes).
Stick with SE/SP versions. That way you get the better suspension and dry clutch. The SP also has Mag wheels, but all this costs more.
$6k is a good starting number but expect the prices to go up for the better machines. Check with the forum before handing your money over.
_________________
james
Its not how fast you go...Its how you go fast.
MC21 Rothmans
RS250
RC31
CRF250X
748R
Porsche (many)
http://members.rennlist.com/j911brick/rennlist3_002.htm