Moodle is open source software and you can get it for free forever if you are willing and able to do the setup, hosting, and support yourself. Or you can pay a Moodle partner to do it for you.
Totara is based on Moodle and is more oriented for corporate training. It is, however, not free. A free trial policy will depend on the vendor you get it from. Many Moodle partners also offer Totara.