Moodle Sandbox: this is an empty sandbox environment where you can do whatever you want as a student / teacher / administrator. Resets every hour on the hour.
School Mount Orange: like Moodle Sandbox, but preloaded with some realistic content. You can also do whatever you like with various users. Resets every hour on the hour.
Moodle Cloud: sign up and you have a free Moodle site for 45 days. Convert to a paid plan if you want to keep it - download a backup of your work if you want to go somewhere else.
Moodle Downloads: all sorts of downloads to run Moodle yourself.
Moodle Services: if you want a large site with lots of possibilities and you can’t do it yourself.