Before this is over, you're not going to like me.
First off, I'll say it looks like it's in great shape.
It might make a reasonably good commuter if you put roadish tires on it.
Yes, it was state of the art in its day.
I said all that to soften you up.
How much is it worth?
Maybe $100.
Why only $100? What's changed about mountain bikes since '97/98?
The list is long...
No more 26" wheels -- now 27.5 or 29"
No more rim brakes -- now disc
No more front derailleurs -- now 'one by' drivetrains
No more archaic frame geometry -- now 'modern geo'
Thru-axles in hubs
Tapered steerers in forks
Dropper seatposts
Wider rims & tires
Far superior suspension
I know you're sentimentally attached, but to the average 2023 mountain biker, your old bike is just not worth anything, really.
But you may find someone who wants to get into mountain biking that doesn't know much about the sport or all the stuff mentioned above.
Somebody like that might give you $100 or so.
Sorry. I don't like being the bearer of unwelcome news. Good luck.
=sParty