I don't know any online marketplaces that aren't more than 50% scammers. Hell, Paypal aids and abets the scammers on ebay. The last few times I've attempted to use Craigslist I've seen plenty of scammers but the worst part is actually the real people I talk to who just waste my time with "I'll take it off your hands if you give me $10". What's even the goal there? Do they just email every single listing with that crap, hoping someone is desperate enough to pay someone to haul away their furniture? Online marketplaces really undermine my remaining faith in humanity.
I have had only positive experiences with Swappa, both as a buyer and as a seller.
Swappa covers only electronics though. For everything else I have decided itβs not worth dealing with the people you mentioned on e.g. Craigslist and just give it to Goodwill.