What is the difference, between the 10 SSL & 100 form submissions/month?

I received an email that I was reaching my quota submissions of 10 SSL, what happens to forms submitted after the quota is met. Also, what needs to be done to take advantage of the 100 free submissions per/month. I like this product and would like to continue using it, but I'm not at the point where I can justify upgrading right now. 

A submissions is secured when it is sent through a secure connection. To do this the form should be browsed or embed with SSL script (i.e. HTTPS while non secure is HTTP). When SSL submissions are used, the transfer of data between the browser and the webserver is secured. This ensures the safety of the data transferred from possible hackers.

To use secured version of your form, the "Secure Form" checkbox needs to be checked on when copy your form's embed codes in the Embed Form wizard:

Keep in mind that if you embed the secure form, it will only allow you to receive 10 submission per month in a free account, once it reaches the limit, the form will be disable until following month when the counter is reset. Let us know if you have more questions.