Agency Model

I currently have a shopify store but now i am introducing a Direct sales Agent model. What i would like is that there is an "Agents" tab that you click on then it has tabs about becoming an agent, earnings and register section. Once registered i would like the Agent to be able to buy off the current website but they will get a 50% discount on all purchase - i was thinking they get allocated a promo code but maybe there is a better way? Is this something that is achievable?