The Savage 99 is more work than the average bolt action for a couple of reasons. First, there are two extractor cuts to be made (actually, only one is an extractor cut but the other cut looks like....). In addition, the forend attachment piece has to be dovetailed into the barrel. The location is fairly critical. Unless the barrelmaker supplies a blank contoured precisely the same as the factory barrel, some re-contouring and/or stock fitting will be necessary.
I'm assuming your Savage is in a 308. Any other caliber and the magazine spool will need modification. Add money. If iron sights are desired, add more. Dennis' estimate is a good starting point. Regards, Bill