Free Sites Are Forced to Purchase $0

I'm new so hopefully this an easy one. I want users to be able to create free sites and update them without having to go through the purchase process. One of my levels in Pro-Sites is free, however, when a user creates a free site, they are not added to this level. When they try to login, they are prompted to pay first and the free option appears with the paid option. The process, even though the site is free, takes the user to the PayPal screen (I only have PayPal enabled). I would like for new sites to automatically be registered with Pro-Sites as the FREE level I have setup. How do I do this?