In saying all of this, you can negotiate the commission rate with your Realtor.
In addition, the agent who is listing your home for sale will have to split that commission with their office broker. On top of that, the agent will have to pay self employment tax (at 15%) and state and federal and state income tax (varies depending on your state, but averages somewhere around 30%).
So yes, the commission may be a large number but only a fraction of that ends up compensating the agent for his or her time.
Keep in mind that you get what you pay for, and if you only shop for the lowest price, you will probably get the lowest level of service, and that may be ok for what you are trying to accomplish. However, if your goal is to sell the house quickly and net yourself the most $$, interview the agents and find out what they will do to earn their commission.
Lastly, for the record, I'm exclusively a buyers agent, so I'm not soliciting your business.
We cannot comment of the agreed commission; the Government considers it collusion and restraint of trade for Agents to discuss it openly. (or some such violation.)
Attorneys cannot discuss it either.