Is Microsoft's Office add-in program free for all publishers?

I have a service where I charge customers for data. I want them to be able to get that data via Excel, but the old VBA addins, which you could distribute with an XLA file, are increasingly being replaced by "Office Addins".

The best way of distributing these appears to be through Microsoft's addins store built into Office. However there is no obvious information in any of Microsoft's online documentation about costs (if any).

• Does Microsoft charge money for free apps on the addins store?
• Does it take commission for apps with in-app subscriptions?
• If yes for the latter, is one able to publish a free addin but charge clients externally (as I am currently already doing), thereby avoiding paying any addin store commission?

Microsoft does not charge or take a commission for add-ins that you offer through AppSource (aka: the store).

UPDATE: I work at Microsoft and got this from official source. Also see here: https://learn.microsoft.com/en-us/office/dev/store/appsource-submission-faq#can-i-submit-a-paid-app-to-microsoft-appsource