Blue Book of Gun Values, auction sites.
Professional appraisal
You cant, unless you can identify the rifle correctly. Need to know ALL the markings, barrel length, caliber, etc.
Take the rifle to a gun shop so they can figure out what make, model and caliber rifle you have. There is no 84 caliber long rifle.
They only made this boys rifle for 5 years and they are difficult to find in good working condition. I have one in my personal collection and value it at $200-$250
You need to find out what model your Winchester is. Just knowing the caliber won't do. The same serial number will exist on almost every model. If the rifle is a model 670A it was an 'economy' version of the Model 70, sold in department stores. Value today at retail is $250-$300.
These rifles are close copies of the early Winchesters. They are not worth much. Does anyone know where I can find parts???
50-100
Winchester model 100 (rifle) in 100% shape is worth $550.00 in the 308 caliber. Winchester model 100 (carbine) in 100% shape is worth $795.00 in 308 caliber. If you find a model 100 in the 284 caliber consider yourself lucky and buy it, dinosaur bones are easier to find.
You will have to contact the company to find out.
I have a Stevens model 75 rifle. I just ordered several books on this web sight "www.cornellpubs.com". You would need to check on books in the early 1930s. Hope this helps!
Basically impossible to do with just the serial number.
Many do, but, not all the time. You will have to call to find out.