This is actually a very common question, though unfortunately doesn't have a simple answer such as 1+2=3.
There are various types of commissions and various reasons someone would be willing to pay a higher commission. On the low end there are FSBO(For Sale By Owner) websites that will charge you a flat fee in exchange for listing a property in the MLS, and many will require you to offer what is called a Co-Op Commission, which is the fee paid to the agent that brings the buyer to you.
Commissions can be whatever someone is willing to work for. An agent has overhead costs to consider when deciding whether to work for the commission a seller is offering. There are costs to maintain licenses, continuing education, marketing, and overall the cost of making a living. Just as you trust a doctor with medicine, an attorney with litigation issues, you trust a Realtor with guiding you through the process and helping you get top dollar for your home.
When deciding to list a home for sale, speak with the Realtor to see how they plan on marketing your home and what their plan of action is to get your home from for sale to sold.
One agent may charge you .5-1% less than another, but in the end, who do you feel will do the best job for you and be the best at communicating with you so you know what is going on with your home. Just because an agent can sell you on listing your home with them, doesn't mean they are the best ones to walk you through the process. The agent charging you a higher commission may actually be working much harder for you, and may actually make you that money back in the sales price they attain for you in the end.
Don't be afraid to ask, the dollars are in the details ;)
Paul Cionczyk| Coldwell Banker Residential Brokerage |Broker
312-433-9931 | PaulCionczyk.Broker@gmail.com |PaulCionczyk.com