Simply giving the age, serial number, and chambering of a rifle isn't a good way to determine a value - since you haven't given enough information, nor posted any good/detailed pics, that would allow anyone to make any such judgement in an intelligent manner.
In real estate, value is based upon location, location, and location.
In guns, the value is based on condition, condition, and condition - meaning the % remaining of the original issue condition, and not simply "good" or "excellent".
If you cannot supply additional information, and/or pics, another way to roughly determine a value would be to surf gun auction sites, like gunbroker.com or auctionarms.com, for any closed/sold Savage 99's in .22HP in a like condition as yours, to see what someone would actually pay for one - the true indicator of value.
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