$1200 For a '97 would be a good price if it is in reasonable shape. Things that you should consider are the tread wear on the tires, time since last top end rebuild, the condition of the plastics, any extras, spare parts, etc.
Wanting a 2000 or newer and only having $800 doesn't go together. You can buy a reasonable bike from the mid '80s for that much but a 2000 model for $800 would probably not be in very good condition!
Do you have the necessary riding gear? You will need helmet, goggles, and boots as a minimum. Gloves, knee pads and chest protector are highly recommended. A good pair of riding pants will keep you from tearing up your jeans. The gear will set you back $400 or more if you go buy new.
If you don't have the gear what can really sweeten a bike deal is getting the riding gear thrown in. A lot of people who have been riding for a long time have piles of this stuff in their garage that they would be willing to throw into a bike deal. Some people are getting out of dirt bikes completely and may throw in all their gear. If it happens to fit you can really make out.
I don't recommend buying a bike unless you can afford not only the bike but the necessary riding gear AND have some money left over for maintenance. Two stroke oil, chain lube, air filter oil are just the basics for riding. When you ride things will break: brake and clutch levers are easily broken. Handlebars get bent. Tires go flat. Nothing worse than having spent all your money on a bike and you still can't ride because a $20 part is broken.
Rod