I just got this email yesterday from them. It looks like all you have to do is to know a member. Here is an email you can use as a members email to sign up. Enter this email
mrpatience1@live.com when it asks for the members email it should work.
We are now open for your friends and family to join the StudentRate community.
How Does It Work?
Your friend or family member can visit StudentRate - Local and National Student Discounts and use their own email address (all email extensions will work e.g., .com, .net .us etc) to register,
Select “I am a family member of a Student” during registration
Enter your, when required, email address (.edu or alternate)
They will receive an activation email automatically and can take advantage of thousands of deals/discounts.
So -- invite them now, spread the word.