Oh, this is shady: a picture frame with a built-in microphone and a GSM phone. Call into the number assigned to the picture frame's SIM and listen in at any time, with stand-by time of up to two weeks.
It's £130 and includes a SIM card, but no service plan is mentioned. Presumably you could use any SIM and any service. The seller is in the UK and GSM frequencies are not listed, so I'm not sure if it'll work in the US.