Totara is basically a fork of Moodle which added more business orientated functionality (possibly over simplifying but that's the general gist of it). Although Totara had a bit of a play with a community edition ("Seedlings") that died a death and was behind core Moodle by a couple of releases anyway. Although, I believe there may be something new on the horizon.
Along the same lines is Remote-Learner's ELIS. Remote-Learner, unlike Totara, publish their enhancements/added functionality to the public as plugins on github. Therefore, if the reason for the question is purely financial it would be worth having a look at the functionality ELIS can bring to the table and compare it with what you get with Totara (bearing in mind you would then have "the cost" of maintaining a purely open source system unless, of course, you moved to a commercial arrangement with Remote-Learner similar to your current deal with Totara).
Another option along a similar vein is IOMAD which could also worth comparing to see if it would meet your requirements. Can't say I've looked into IOMAD much since it was released but I have read good things about it.