You only need to purchase the DVD`s one time.

I have used the invite system with leads that were recomended in GDI made easy. I have used them almost every day for about 3 months without any problems and actually got several sign-ups. Last week my site was shut down down for about 24 hours becausce
someone reported that they were spamed. I had all of the information needed to prove that it was nor spam.  I received an email from GDI..they put my site back on line and said that if that happens again, that privelage may not be extended the next time. If the information that they wanted had not been saved, it would cost $199.00 dollars to be renstated.  So my invite system use is over.