Thumb Score: 0

Luxomo has a nice selection of sunglasses under 20, bought a few times from them and they include a case and they add a cleaning cloth and a soft carrying case. Some of the models here have been on sale for a bit less but others are very good deals, for example:

Mens Calvin Kelin Aviators: https://www.luxomo.com/calvin-klein-ck8037s-223-men-s-sunglasses​ [luxomo.com]

Carrera unisex: https://www.luxomo.com/carrera-5019-s-0na6-uz-sunglasses​ [luxomo.com]