Downloaded free scan of malwarebytes. Was asked to purchase 'freshmac'

Whatever "Freshmac" is, it's definitely not in any way related to Malwarebytes. It wasn't Malwarebytes that caused that pop-up to occur, but it could potentially have been an effect caused by removing something you had installed on your system. (Some programs, such as MacKeeper, will display an alert when the app is removed.)

Were you directed to a website for "Freshmac"? If so, do you remember the website address?

I found a copy of Freshmac. It's junk... reports that a perfectly clean macOS system needs "immediate attention" with a "high" number of (nonexistent) issues.

Malwarebytes will be detecting that before the end of the day.

Fortunately, removal of Freshmac is pretty easy... just delete the app and restart the computer (or kill the Freshmac-helper process) and that's it. There will be some random data files left behind, but nothing concerning.

We've got a couple other rules we're working on before pushing up the signature update, but if you run a scan with Malwarebytes later it'll clean up those last remaining bits.

Here is the legitimate copy of Malwarebytes. This is the full package. I have no idea what you have. I have never heard of Freshmac.

I have no idea, but hopefully, yes.