Pair of Glasses
What would you expect a pair of prescription glasses cost you?
$100? $200? $500?
Well, without insurance the pair of glasses I received would have costed over $520...

And this didn't even include an eye exam.
Without insurance, I probably wouldn't even have considered getting a premium (read branded) frame and upgraded lenses. For many people without too complicated prescriptions or other circumstances like me, purchasing prescription eyeglasses online can be a great alternative. Warby Parker is probably the most well-known of online eyeglasses retailers. I've had great experiences with Coastal for eyeglasses, which offers premium brands and the lesser known brands at affordable prices. You can usually get comparable prices online without insurance to brick and mortar stores with insurances; probably a result of the reduced operating costs and increased number of customers made possible by the Internet.
But there are benefits of brick and mortar eyeglasses that you should be aware of. The convenience: Having a independent optometrist on site, trying numerous frames without waiting and shipping back and forth (without those terrible digital try-on applications), frame adjustments (pupil distances, temple adjusts). The most important benefit is getting individualized service, particularly for those who have extremely high prescriptions and other uncommon needs.
And the high prices for premium frames? Well, that's an entirely different issues that has much to do with Luxottica, the largest eyewear company in the world. They are makers of Ray-Ban, Oakley, Burberry, and many more.