I'm a fan of slim cases that don't have a lot going on. I picked up the Diztronic case from Amazon for $10. It's slim, fits the phone well, and has a nice matte finish on it. Probably not the most protection when it comes to drops, but I mainly was worried about the back glass getting scratched so this does a great job.

https://www.amazon.com/gp/product/B06XC3PM6J/ref=oh_aui_detailpage_o04_s00?ie=UTF8&psc=1