I would use an existing service like JVZoo. They already have the platform and structure and you don't have to reinvent the wheel. There are Wordpress plugins that will help with affiliate tracking as well, but I don't trust them as much (which is simply my opinion, not a fact about their validity).

I do believe this specific idea you've described for referrals is a good one, because of the reasons I discuss in this video:

https://www.youtube.com/watch?v=iJ9OLCZ1KRc