I'd recommend checking out Craigslist, Facebook Marketplace and OfferUp (local) first. You don't pay fees on these platforms. However, in exchange for collecting more, you might deal with more hassle from buyers, headaches, people that don't show up, etc.
I'd recommend online selling for things that are small and lightweight. You pay a lot less in fees for this class of items.
Finally I'd recommend against Amazon unless the things you're selling are like new and would be found in a retail store. Amazon is just a giant retail store, it's not really the platform for collectibles and such.