They could backorder them like everyone else does. Advertise a product and price. Accept orders at that price for existing stock and scheduled deliveries. And repeat that process as more become available.
As an optimization, allow a fixed-sized queue of "pre-orders" at the same price. Though you have to be careful with this because you're selling things you aren't guaranteed to get. Amazon can cover the losses from mistakes here, small vendors can't.
They could backorder them like everyone else does. Advertise a product and price. Accept orders at that price for existing stock and scheduled deliveries. And repeat that process as more become available.
As an optimization, allow a fixed-sized queue of "pre-orders" at the same price. Though you have to be careful with this because you're selling things you aren't guaranteed to get. Amazon can cover the losses from mistakes here, small vendors can't.