Anyone can join Simple Check!
Either download the Mobile App, or visit the web console at https://app.mysimplecheck.com..
At the bottom of the login page, click "Don't have an account? Sign up"
On the new screen, fill out your information and click "Sign Up"
An email will be sent to that addess with further instructions. You will now be logged into that device with your new user account. You can use the email and password to log into other devices as well.