The more you do to a lense, or the more you expect it to correct, the spendier it gets.
I've got single-vision poly lenses (I need the poly for impact resistance, and it keeps weight off of my nose...) which come bundled with the UV coating (I don't have a choice. Get the UV coating or get a hole burned in the back of my eyeball at this point. VisLight focusses to a useful image, UV to a pinpoint.)
I found out this last time that they do the "photogrey" (what's it called now, "Transitions?") with the high-impact, high-index poly - I've been waiting for that!
I get the 1m/m centre thickness to keep the lense weight down.
Designer frames I don't care for - while my frames aren't clunky (like issue BCGs,) they're not "super-wifty." I get the spring temples for comfort, I think my frames run somewhere around $100-125 for the thing. I keep two sets - that way, when I get replacement lenses, I can send out one frame with them and the the lense ground to fit - then leapfrog the next time. Genetics and trauma run against me, I almost invariably require new lenses every year.
Progressive corrections are more difficult to grind than traditional bifocal/trifocal lenses, simply because you have to "hide the lines." If they didn't, it would cost somewhat less.
Two factors that can drive up the cost of lenses in a hurry:
1) Progressive correction (for the reason given above.)
2) High-diopter correction. Why? There's this little thing with lenses called "chromatic aberration." It's the same thing that makes a prism work - different colours of light focus at different points through the same lense - because the different colours have different wavelengths, and bend differently.
At low levels of correction (say, <5 diopters either way,) it's not a big problem. You get up around where I am now (>-10 diopters & +2 cylinder for astigmatism,) and it becomes a big problem.
There are three basic corrections ground into a lense.
--Sperical or sphere (or diopter) - this is the basic correction for myopia or hyperopia (nearsightedness or farsightedness.) Postive diopeters for hyperopia, negative diopters for myopia.
--Cylinder - this is the correction for astigmatism (a "wave" deformity in the lense or cornea of the eyeball.) This always has a number (degree of correction, typically positive) and an axis (direction in which the deformity lies, 0-180*.) This is also why "toric" contact lenses were developed.
--Prism - this is a correct for amblyopia (cross-eyedness.) Usually a simple matter of a number (degree, typically positive,) but can also include an axis (in case the prism needs to be rotated from a horizontal correction for an eye that isn't turned merely "straight in" or "straight out." Zero to 180*, again.)
If it's offered through your workplace, you may want to look into VSP. It's the only vision/optometric insurance I can think of offhand, but it's pretty decent. We pay a $15 copay for an exam, lenses are covered annually and frames biennially. They also automatically add things depending on your needs in the coverage - for instance, the UV coating and high-index/high-impact poly are automatically covered for me. The 1m/m centre thickness is a simple change in grind, so it's merely an order option (making the centre of the lense thinner allows the edge to be thinner as well, reducing the overall weight of the lense.) Basic sphere/cylinder/prism correct is always covered - since it's what you need. And, it's accepted pretty much everywhere, although copay usually varies by employer (how much they're willing to fork over for the plan itself.) However, VSP is usually an option - and doesn't cost the employer overmuch, since an optometrist isn't an MD
