Toric meaning ‘somehow heavier on the ‘bottom’ so it stays properly aligned on the eye’, of course.
And they’re not terribly expensive; it of course depends on the brand. The toric lenses I wear cost about $35 for six lenses (so $70/six pairs), but I’ve seen ones that cost twice that. (And regrettably, my astigmatism is so bad that when I asked once if I could get away with wearing normal lenses, the ophthalmologist actually laughed. “Well, you could try, but you still wouldn’t be able to see and you’d get a really bad headache”).
I could be wrong about this, but I was under the impression that lenses aren’t custom-made per patient the same way glasses are, but the more ‘popular’ degrees of correction are mass-produced and usually kept in-stock at whatever retailer. My only cite for this is being told by various small suppliers (ie, eye doctors) that my lenses have to be special-ordered; they can’t just give me a pair then. I could have misunderstood, though.
No, that’s not what it means. (And don’t feel bad about that. I’m in optics, and I didn’t know what it meant at first, either). “Toric” means that it has two different radii of curvature along two mutually perpendicular directions. This lets it correct by different powers along the two different axes, which is what you mean when you have astigmatic correction. The “toric” name seems weird, since it implies something doughnut or bagel-shaped, but it’a appropriate. But the center of the lens isn’t the center of that doughnut. Imagine a sliver from the outer edge of a bagel. It will have one radius of curvature along the plane containg the hole and along the plane that takes the biggest proportion of the bagel (which is nowhere near your hole, which is the radius of the extreme outer edge of the bagel. It will have a smaller radius along the perpendicular direction, which takes a “cross section” through the “arm” of the bagel (so that the slice looks like two separate circles). If you were to use, say, an ellipsoid you’d get two different radii at the apex, but the radius would vary as you moved away from the center. With a torus the radius is the same everywhere along the major axes.
The weighting is a separate addition, a bit of wedge through in atop the rest of the curvature.