Is there a way to put a limit on the number of sumbissions?

I have a form for a RSVP. The party will only let us have 500 people. 

Can I limit the form to count a submission button so when the tracker of RSVP is filled out 500 times it will close the form?

You can update your Form Status in the Form Settings page. In the Form Status section, select the "Disable on submission limit" option. After that, you can adjust the Limit and Warning Message to your own preferences. Here's a screencast guide that you can follow:

Please try it and let us know if you need further assistance.

Vincent, 

Can have up to 5 RSVP for each submission which would take that away from the total number of submissions. 

How can I make that happen?

If the count is based on the number of RSVP in a submission, then I would suggest that you use a widget like the Inventory widget or the Quantity Gift Registry widget.

http://www.jotform.com/help/252-How-to-Add-a-Widget-to-your-Form

The available quantity left will be based on the total of all the entries in each submissions.

If, for example, the first person to submit the form entered/selected 5 in the widget that has 500 RSVP available and submitted the form. The next person to fill-up the form will see that the available quantity is reduced by 5 (495).

You can make the widgets required so when there is no available quantity left, the form cannot be submitted.

https://www.jotform.com/help/546-How-to-Set-a-Field-as-Required-or-Non-Required

Please give it a try and let us know if you need any further assistance.