The LEGO® Group’s Powered Up system is poised to replace Power functions, but previously you had to buy a whole set to get the components. Now, they are offering most of the components and sensors as individual purchases under the Powered Up theme in their store. This can save you a few bucks depending on what you need, although I’ve seen the App Controlled Batmobile on sale once for cheaper than buying just the basic hub with two small motors.