Is there a “set commission” charged to consumers by Realtors®?

No. The commissions set forth in listing agreements are discussed and negotiated between the Seller and Listing Broker. As NAR states, “[t]he market decides commission rates, and commissions are always negotiable. Consumers have the choice of who they want to pay and how they want to pay them.” Moreover, Buyer Brokers are free to negotiate compensation with Listing Brokers, even if it is different from what appears in the MLS.  
Commercial Council