You can always add add ons to your Bricr subscription. It doesn't matter which Bricr plan you chose.
Where do I add add ons to my subscription?
Users with Admin permissions can add add ons to a Bricr account subscription.
You can add add ons to a paid subscription any time.
Go to Settings > General > Subscriptions and click on the desired partner program.
The affiliate program may also require you to contact them to sign a contract and make financial arrangements with them.