It cost me 8$ for a 1.5oz. tube.
I've been using just a little dab (about the size of a small pea) to cover my face after I've applied my sunblock and let it set for a while before either airbrushing my foundation or using creme.
It's SMOOOOTHHH in application. It's this weird sensation of your fingers gliding over your skin. It is not oily, just...strangely smooth. It makes me think of those liquid suspended powders that have unusual properties.
I do feel like it creates a nice soft focus effect on my skin. Too bad I immediately cover it up! If I'm not wearing make up (rare) it does make for a really nice fresh clean look. As for it's protective qualities, I've found that it increases the longevity of my airbrush makeup which I just spray lightly over my face. At the end of the day, my foundation at my lip line, and under my chin is still completely there. (I often rest my chin on my hand, and I'm not too careful when I drink to not let the liquid touch my skin).
However, I don't really see a big difference when I wear creme foundation. My creme foundations have oil in them, and also require that I brush/rub my face with a sponge, which could disturb the protective layer from the Monistat gel and render it less effective. It does make application much more smooth however. No real difference in the prevention of creasing around my mouth.
On my eyes, I do feel like it helps hold in moisture, but I'd bet not wearing dry eyeshadow and packing on moisturizing products would help even more. I don't think its particularly effective in this regard compared to other things.
Overall, I'm happy with how it performs, and I think I'll continue using it.