Where do I sell my iPhone 5s which is brand new but it was exchanged at Apple since I broke my old iPhone 5s?

So a few months ago I broke my old iPhone 5s and went to the Apple store to go exchange it for a new one. I got a iPhone 8 for Christmas and now that I can't go back to Apple to exchange it again, Where do you guys think is the best place to sell it?

EBay

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