Where can I buy or sell things online with bitcoin?

I think this is what bitcoin is missing. A buy/sell platform that is not for illegal goods.

I'd love to accumulate bitcoin by selling some old stuff I have (Laptop, lego, etc), but the main hassle is that I'd have to sell it for fiat somewhere (I despise ebay), move the money to an exchange, and then buy btc, which I'd then lose maybe 10-20% in fees.

Are there any online platforms I can use to sell stuff online using bitcoin? (Not illegal stuff)