How cheap would a WIFI chipset have to be to make dropping a spambot into teapots worthwhile?
Texas Instruments is offering this chipset TI CC3000
at $10 ea
which would seem to be a minimum feature set, since in the absence of a PC of some sort having its own TCP stack,
you'd need that built in.
This seems more likely something that an attacker would have to 'shotgun' at a target (distribute to vendors selling to intended victim) vs 'carpet bomb' (sell to everyone).
Alternately, could this be a feature teapot that got hacked by spammers? A teapot that sends you some sort of message over your local network when it is ready, instead of relying on you to hear a possibly weak whistle, might be worth another $20 or so more.