and faster. they re experimenting with drones, drivers and self-driving robots. it s the most expensive because there s a huge van that is starting and stopping and the driver is getting on and off and knocking on doors. that takes time, and that s something that the driver needs to do for every person. home grocery cldelivery services are convenient but they re not always cheap. amazon s membership costs $300 a year. one of skype s founders believes he can bring the costs down with self-driving robots. reporter: what does it have in it different than the cart? the cart doesn t have nine cameras. ours does. it has electric motors and other sensors. the robot is observing pedestrians and is navigating on