I got my Warby Parkers at a pop-up shop but they have try-before-you-buy as well. I've loved them to bits.
Also if you're a Costco person, I got some giant prescription sunglasses, which I need for medical reasons, and they weren't that expensive. Their selection isn't super quirky or anything but the glasses have served me well for years (my prescription hasn't really changed in all that time).