Good morning Bill...
There are many brokerage firms that are not "full service" firms...in a case like that, the agent will take your listing and put it on the MLS for a fee...that's usually the end of that. They don't negotiate contracts or speak with buyers and/or sellers. Those are known as discount brokers. I would imagine that any buyer, or seller wouldn't want to go to a "discount doctor"; therefore, commission is based on several things. It isn't set in stone and there is no "fixed" commission rate. I have had repeat clients that I have given a commission reduction to, and then I have had commissions, (recently, as well) that have been 10% and 8%. Each of these sales had offers within a week.
Also, the commission is split four ways...the broker and selling agent, and the broker and listing agent. Just remember that all the work really begins when the contract starts. I'd love to help you find a home. Feel free to call me for any questions you might have about the market.