If that is your budget, you're better off with an aperture sight rear/ fiber optic front sight set-up.. The only advantage the scope would have would be in low light. A $100 scope will not do for low light.
Never use see-through mounts. They are not reliable.
Aren't you forgetting the advantage of magnification of the target? That's the primary benefit of a scope, after all. Also, an aperture rear sight seriously reduces light transmission. It will reduce shooting time by about 15 minutes from even the cheapest scope.