If what you are selling is hand made, there's artisans.coop which is not corporate owned. It's just a bunch of small arts and crafts makers who are pooling resources to build a marketplace that isn't there to exploit the sellers (or the buyers for that matter).
There's Tindie for small electronics projects.
Neither currently accept BTC, but that would be a lot easier to change with the coop than with Tindie, since the coop is democratically run.
There was OpenBazaar that was a true p2p marketplace that focused on cryptocurrency, but that died and the attemp to revive it has not seemed to have been going well.
I'm not sure what other options are out there in this space, but I'm always interested in hearing about more good options!