There are a few.

LNBits has a marketplace extension based on Nostr but the UX isn't exactly user friendly.

However cool thing about it is listings are notes so you can send them from a Tor only node and access through a clearnet frontend.

There's another implementation called Nostr Market.

All this is open source and can be self-hosted ofc. Frontend is the only thing to host. Everything else is decentralised.