Tri Bot half price at Tesco direct. (Full size one - not mini)
Cheapest elsewhere I've found is about £40.
It's available on doubled up vouchers too :-))
robot companion. He has a pop top head and animated eyebrows and you can play games with him such as pattern, maze or minefield. TRI-BOT can move in any direction using his three wheels and you can control him using the tilt sensitive remote controller. TRI-BOT is equipped with an alarm and he will make sure you get up as you’ll have to catch him to stop him. TRI-BOT can tell you when he’s fallen over and even avoids obstacles.http://direct.tesco.com/q/R.204-4344.aspx