My own children (10 and 7) enjoy using Prodigy as it keeps them interested due to the fact that it is interactive.
My wife uses it in her district (she teaches 4th grade). She enjoys the fact that she can align her class to where she feels necessary. See embedded picture below.
In the video below I show how to sign-up for an account, create a class, and how to print out the log-in cards. If you do work in a school district that utilizes Google and Google Classroom, I strongly encourage you to sign in with Google as this will allow you to sign up your class using Classroom.
Embedded below is a 1 minute and 56 second YouTube tutorial.