What is the value of a Winchester Model 370 410 gauge?

This is a tough one. I can't find it in any of my recent price guides, but my 1999 Gun Traders' Guide suggests $95 in NRA Excellent condition. That's identical to a similar gun from another manufacturer which is still listed at that value in the 2004 Blue Book. You can usually expect a used gun in decent condition to bring from half to two-thirds of the new price of a similar gun, and new single-shot shotguns go for $89.95.