eh, that's not a bad price I don't think, but, assuming you haven't ridden a 600 before, you'd be way better off buying a cheap, used 250. That has a hell of a lot more power than you think, and without experience, you can easily kill yourself. If you buy that, you will speed. If you buy a bike, you will speed. You'll probably ride like an idiot, and that bike will not be as forgiving of inexperienced throttle control as a smaller bike. You need to learn to ride on a small bike.
DUDE I DONT EVEN KNOW HOW TO DRIVE A DAMN BIKE... I JUST WANT TO KNOW HOW MUCH IS THAT WORTH TO GET IT AND MAYBE RESELL IT OR LEARN HOW TO DRIVE THE DAMN THING
Oh well if you're just gonna re-sell it, I'm pretty sure that's a good price. Ask around locally. If you decide you want to try riding it, talk to your uncle, maybe go 2 up, just to see what kind of power it has. Get your uncle to show you everything, then take a motorcycle course. If you feel confident enough then, give it a try. Over confidence will kill you though.