Many agents are willing to be flexible on commission rates, but it's not something they like to advertise. And most clients are not very comfortable negotiating rates. A lot of it depends on the potential selling price of your home, too.
At UpNest (http://www.upnest.com), we created an online marketplace where home sellers can confidentially submit their homes, and multiple top local agents will compete to obtain your listing. Some agents lower their commission rates to stand out, and every agent that submits a proposal is an experienced agent, so it's not the same as working with a low grade discount brokerage.