I had lost my last set of glasses from 6 years ago. Then never bothered getting a new set (mild correction) but it's started to affect me more while driving, so I got a new pair.
I did get Guess frames, however they were cheaper than some of the other options. Got polycarb, anti glare, antiscratch, single vision, standard index. retail: $590, copay after insurance: $185, submitted the rest to my employer so it was free.
Since my Rx is for distance, I also wanted to get sunglasses. I was quoted $200, no insurance. I passed for the time being as I had heard about an online store from one of my customer's,
www.zennioptical.com. Picked out a set of frames, polycarb, tinted, antiglare, antiscratch, $30 shipped to my door.
I expect the Guess frames to be more because they are brand name, however to get a complete set of Rx sunglasses for 20% of the frames alone for my daily pair is nuts.
I've since learned about about another site called Eye Buy Direct. They seem to have a little different selection but the same basic prices.