I've started dabbling in the Linux operating system, for two reasons -- the Raspberry Pi (a $30 single board computer that runs on Linux) and losing the PIN code for my Bitcoin hardware wallet (which I recovered using an old MacBook Air running Linux).
If you are interested in Linux but don't know where to start, Lifewire has a good tutorial on how to install Linux Mint (one of the many different free distributions) on your Mac or Windows machine without overwriting the existing OS. That way, you can boot into either OS. It also shows you how to install Linux Mint onto a USB thumb drive and boot from that.
Another recommendation: the book Linux for Makers, which is a great intro to the operating system, especially for Pi users.