Ebay if you're willing to ship. If you do it as an auction, look up strategy tips online (e.g., set the auction to end on a Friday evening).

Otherwise look at Facebook Marketplace. I have sold a bunch of things on there over the last year or so. Only about 10% of the leads actually turn into sales, but some things where I have multiple items turn into repeat customers or they get more than one.

You could also try Craigslist but I have had zero luck on there in the last few years.

You'll probably make the most on Ebay since negotiation is limited, if you even permit it. On FM I typically agree to 15-20% off what I list it for; sometimes I list higher with this in mind, but that often leads to fewer responses.

-J.