A standard commission a Realtor receives upon selling a house does not actually exist, though the usual commission tends to be about six percent. The commission is a negotiable part of the contract between the seller and his real estate agent.
A Realtor sometimes agrees to a lesser percentage for various reasons. When the housing market is in a slump, an agent may agree to a smaller a commission just to stimulate business. At other times, he may agree to such a condition if the seller agrees to participate in marketing the house.
The listing agent agrees upon the commission, but he typically halves it with the buyer's agent. If the commission is six percent, he ends up with three percent, even though he paid advertising and open house expenses where applicable.