Motorola security camera for just over just over £40. Add a 5p screw so you get 20% discount for anything over £50 until Jan 2 (£49.99 on promo now - full price £69.99).
Easy to set up (took about 3 mins), links in to WiFi, and view anywhere from your phone/tablet remotely. has motion detection, sound detection, temperature display. 720p video. Sends messages to your phone when anything happens (all notifications are adjustable or can be turned off). if it detects movement it sends a still of what triggered the motion and will save the recording in a time line so you only have to view what happened. You can view live stream or just look when alerts come in. I've got one set up at our door entry.
Amazing bit of tech for the price!