Where can I purchase a Pixhawk 2.4.8 at the present?

Hi all!
I’m a student at the university, and I want to buy a Pixhawk controller on a tight budget. I have a BlueROV with a Pixhawk 2.4.8 version, which was provided by my school, but I’m concerned about damaging it. Therefore, I would like to buy a new one when I’m in an experience period, and I also looked up some online shops, but they’re quite unreliable. I would appreciate it if you could recommend one for me!