Seems like this could be an interesting niche for a fediverse project. The only option that seems to think in that direction that I could find is Epicyon.
Seems like an ideal application of the federated technology. Start small as a neighbourhood sharing/bartering network and over time it can expand easily to cover an entire city or such.
Probably not what you’re looking for, but Hubzilla has a
cartaddon that is an online store you can host in a channel. Documentation is scarce and it’s a tad on the primitive side, but useable enough for simple shops.Yeah, I thought about that too and I remember that a reputation system was extensively discussed for Hubzilla 1-2 years ago. But yeah, not really what I had in mind. Although I guess it would probably be feasible to implement something more like ebay etc. as a Hubzilla plugin.