I agree with rockabilly, it's very hard to determine the price/value.
Start with the cost of a 98 action for around $60, assuming it's solid, and work up from there. Barrel, scope, stock, condition, previous gunsmith work, all must be considered. If it's just a .243 bolt action you're after, remember you can get a Stevens 200 new, for around $260.
If you're buying a sporterized rifle, be sure to have a gunsmith check it out first. Don't get stuck with a dangerous bubba.
Good luck,
MH