I've always followed the normal route--I have employer provided vision insurance, I would get myself tested every two years by a optometrist that my insurance covered, and I would buy glass using the prescription from the optometrist or a glasses store supported by my insurance. I don't have anything special in my glasses--single focal, no tinting or light sensitivity, and my glasses weren't remotely stylish, and I'd pay ~$50-70 after insurance.

I recently lost my glasses in a pond filled with alligators, so I wasn't going to try to retrieve them. I figured I needed cheap glasses until my insurance would cover me again. I had an old prescription but it was over a year old. I looked at Warby Parker, but they seem to require an actual prescription. So I tried Zenni Optical because all they need are the correction figures for each lens, they don't require an actual doctor signed document. Something I've always felt was weird--its not like prescription drugs, and I can decide if the glasses don't work, and a 18 month old prescription is better than no glasses.

So $35 shipped for glasses and frames, and they had a lot that were cheaper. The seem to be very good quality, they seem to work better than lost pair (the prescription didn't have a pupillary distance, so I had to measure it. My eyes are pretty wide, and a lot of lenses can't accommodate my PD, so I wonder if the optometrist just figured close enough for lenses with a lower max PD.) Before this I had no idea how much markup was in the cost of a pair of glasses. Now I'll still get my eyes checked locally, but $30 glasses is better than what I can get locally even after my insurance.