For furniture, the best way to sell them is through Craiglist online. They do not charge an insertion fee nor a commission if the pieces sell.
Another method would be to post them on Chairish.com. They do not charge an insertion fee, but they do charge a 20% commission upon sale. The benefit with chairish is that they help arrange the shipping and transport of the furniture.
You can also find a vintage and antique shop in your area, preferably one that accepts consignments and they will sell it in their shop on your behalf for between 40% - 50% commission.