Consignment shops take a cut of the profit but handle the marketing and selling process for you. Private sales on marketplaces require you to manage inquiries, haggling, and pickup [2].
You can usually get a decent return on your furniture, especially if it is in good condition, while still offering a bargain to the buyer.
The primary benefit is cost savings. You can often find high-quality, solid wood furniture for a fraction of the price of new, low-quality particle board furniture [1].
Don't be afraid to offer a lower price, especially for items listed for a long time.