I love eBay, for both buying and selling used items that are viable to ship.
We let CraigsList get broken, with seemingly much fewer sellers and buyers than it used to have.
I tried Facebook Marketplace, which is where most local buyers&sellers seemed to move to. But I won't install their app, and the notification emails only sometimes came through. (One buyer became very irate when I didn't respond promptly.) Also, their pretend E2E encryption for messages on their Web site was just annoying (like a dark pattern intended to make people hate E2E, while not actually providing any significant security).