Link to ToS: UI Add-On Development Policy
What I am referencing:
1) Add-ons must be free of charge.
**All add-ons must be distributed free of charge. Developers may not create “premium” versions of add-ons with additional for-pay features, charge money to download an add-on, charge for services related to the add-on, or otherwise require some form of monetary compensation to download or access an add-on.
Reddit Thread (With a photo of the paid options that break the above rule) -** https://www.reddit.com/r/classicwow/comments/1x8iemd/xaryu_and_esfand_promoting_a_30_usd_wow_forever/
So, are only Streamers allowed to promote paid, 3rd party services for WoW? Who else is allowed to do this?