I need an automation to connect the course site to Mailerlite

Hi there,
I have a Masteriyo plugin for WordPress for a course and I need to create an automation, so that each person that buys a course is added to Mailerlite and gets assigned to a group.

Happy if you're able to do it via Zapier or Make, though that integration doesn't necessarily come up.

We get a confirmation email to admin about the course being purchased, so perhaps there is a way to use that to automate.

Happy for your suggestions, but would prefer not to pay for extra software (we will probably have under 100 events per month).