I wouldn't give more than $50 or $60 bucks for one, unless it had some exceptional wood, and good lines to it. I've got one that looks blonde, with rosewood forend tip and grip cap, deeply hooked grip and rollover cheekpiece. I let the grandkids play army with it. I've got another one with fairly conservative lines, nicely figured and colored black walnut, that has a polished/blued Winchester in it, and it'd take a fair bit of coin to get that one from me!
In reality, value is what someone is willing to give for it.