$30
Nittaku Poromeric Hard Case
One of the better cases on the market. Proper hard case, can fit 2 rackets and a few balls, has ventilation holes. Mima Ito uses it.
https://i.imgur.com/ajdz9Ej.jpg
https://i.imgur.com/yFb6KLo.jpg
https://i.imgur.com/wKEwRzm.jpg
$10
Xiom Hard Case
Really nice...