Becoming a real estate agent on the side

I'm toying with the idea of becoming a real estate agent on the side. I know a lot about houses and the various areas around my city. It would be a service I would gear mostly to friends with very little advertising (I already have a good salary).

My questions are:

• Is this worth it? Or am I over simplifying selling houses on the side?
• If I want to buy a house, can I be my own agent and essentially get a discount on the price of the house?