Member kickback system?

On our CB website we have free and paid memberships. We would like to introduce some kind of kickback system.
What we would like is the following. An existing member can introduce a new member. When this new member signs up we would like to pay back the existing member a small fee, like 5 USD. Or give them 5 USD discount on their next renewal.
Is there some plugin that can do something like this? Thanks for your suggestions!

Easiest approach is to have a field that stores the discount amount. This could just be an integer field or even a points field. Next you can act on the CB Invites trigger invites_onAfterAcceptInvite with a Field action to increment that field when one of their invites is accepted. Next you'd have a promotion in CBSubs that's based off the value of that field to offer them a discount. If you want to give them money you'll need to use an affiliate tracking system like iDevAffiliate or PostAffiliatePro, which CBSubs does integrate with.

Thanks for your reply Kyle. Where do I set this Field action? Do I need CB Auto Action for that?

Do I need CB Auto Action for that?

Yes, see the below example usage.

Global
Triggers: invites_onAfterAcceptInvite
Type: Field
User: Automatic
Access: Everybody
Action
Field: YOUR_INTEGER_FIELD_HERE
Operator: Add
Value: 5
Translate Value: No
User: [var1_user_id]

That should increase a users integer field value by 5 if one of their invites from CB Invites is accepted for example. A points field should also work.

Wow, thanks Kyle!!!

Kyle, can you elaborate a bit more what I need to do with the User: [var1_user_id] field in the Action tab?
Do I literally need to input the text '[var1_user_id]' (without the quotes) here?