Earlier quoted context omitted.
There's probably a whole market of "notify me when (plane tickets get cheap, apartments look good, tickets go on sale, etc)"
If Amazon had a notification when product X dropped below price Y then not only would it allow people to track that something was now affordable to them, it would allow Amazon to feed back to manufacturers that they could sell N items if they dropped their price to Y.
Maybe we should start trial runs of this feature..