Simple auctions is built on etleneum allowing you to bid on stuff with LN.

They cant confirm and guarantee delivery of goods but with the small user base it's a pretty safe bet. You could mix this with supertestnet's lightning escrow to make it even better.

https://t.me/simple_auction Here is the telegram group, checked pinned messages for current auctions.

I've personally won 2 Weimar reichmarks from the 20's on this site.