Publish what you are selling, go live to show it, and take orders while people watch. Payment is held until the buyer accepts the order, so neither side has to go first.
Show a thing, name a price, run an auction. Viewers order without leaving the stream.
An order holds the buyer's balance rather than moving it. It reaches the seller when the order is accepted, and returns if it is not.
What you search for and what you keep opening builds your feed, sealed with a key that never leaves the device.