Rooting doesn't move your apps to the SD card. but some apps will allow you to move those FEW apps written to run from the SD card to it. (There's still part left in main storage - there has to be or the phone wouldn't be able to run the app.)
SD storage is for pictures, videos, music, documents, that sort of thing. Never count on being able to run your apps from the SD card because most people who "write" apps don't know how to write an app to run on an SD card. (Most of them don't even know how to write an app that keeps its data on the SD card.) An app "written" with an app-writing app (which is how most people write apps) won't run from an SD card.
Cricket not telling you that you can't run your apps from the card is like your car dealer not telling you that you have to stop on a red light, or that your car will run out of gas if you don't put more in the tank. If the Cricket dealer told you everything about the phone it's possible to know, you'd be celebrating your next birthday in the store.