January of 1976...
The Model 99E (Economy) was the last model produced still using the rotary magazine. It was discontinued in 1984 along with the last two remaining original Savage cartridges, the .300 Savage and the .250-3000.
If your 99E is what I believe it to be, it will have either 20" or 24" barrel, but will lack the cartridge counter/indicator on the left side of the receiver and will have a hard rubber butt-plate rather than the steel butt-plate of prior models. Impressed checkering was added to the 99E line in 1966.
Value depends a great deal on condition. The most sought after Model 99s were made prior to Savage's move from Chicopee Falls, Mass. to Westfield, Mass. in 1960... the year the 99E economy carbine was added to the line. The .243 caliber was added to the E-line in 1961.
In 95% or better condition, I'd judge the Model 99E to be worth $500 to $700... but it's value to you depends on how badly you want it. They aren't making 'em anymore, so the value is only going to go up... Up... UP !!!
Good luck with your new Model 99... it has become a "classic".
Strength & Honor...
Ron T.