2 of the data togglers I used before updating to lollipop don't work anymore so I went searching for one that did with no success. However, I've got MobileGo on my S4 and it's more than a cleaner and optimizer... Swipe up from the bottom of the screen and you'll get a "quick-start" menu (tray) that includes a working data toggle. Tap on the network icon (next to the wifi) it and it brings you to the phone's mobile network on/off screen so you can uncheck "mobile data". Found this totally by accident! The app doesn't get listed when you search for a data toggler on the Play Store. MobileGo has an extra step that my previous togglers didn't have but for Samsungs, it's faster than going through the settings menu...