How to create a reservation form and calculate the total base on reserved option.

I'm wanting to use a widget to limit the registration numbers (ticket purchases, appointment slots, etc.) for a camp I am running, but I am also wanting to incorporate the form calculation widget. I would like their choice of week through the limiting reservation widget to also have a calculation value so I can calculate the total amount based on all entries (using the form calculator).

Is this possible (can be through different avenues)?

Right now I can only figure out to use the form calculation with basic form elements, but having registration stop automatically when a week is full is very beneficial so we don't get more kids signing up then we can handle without constantly checking the numbers manually. 

You can put calculations to the widget to assign its own value base on selection. Here's a sample screencast https://screencast-o-matic.com/watch/cFniq5op7W. 

The key here is to use the Update / Calculate Field condition to pass / assign values to a field in case you will need to get the total.

Let us know if you have any questions or if you need further assistance.