Forgive me if this has been already been suggested, but I feel like it needs to be in Meepcraft. Long story short its basically a auction feature. I think what should happen is you can have auctions on or off (muted) so someone doesn't get annoyed by the constant auctions. These will be the commands for the auctions.
/auctionhelp - shows all auction commands, with descriptions.
/auctionstart (item) (starting price) (min bid increment) - starts auction
/auctioncancel - cancels auction
/bid - bids on auction (can't bid on your own auction)
A few more things I would like to point out too.
1. Auction data should be kept in the scoreboard so it doesn't cluster chat
2. I think any rank should be allowed to use all the auction commands
3. Some items should not be allowed in the auction (bones, blaze rods, rotten flesh, basically anything that can be easily grinded.)