I am looking for a widget that will allow us process paymants but also control number of sales.

We run a kayak symposium and people can choose from a 3 day registration and add meals, boat rentals and other items. There are a limit of number or items available and also a limited number or spots to register.  Do you have any suggestions? 

I believe you can achieve your requirement by using the Inventory Widget. With this widget, you will be able to specify the total number of items for sale. When a user submits the form, the items that they selected will be deducted from the inventory.

We also have a Ticket Purchases widget that works the same as the inventory widget but only allows the user to purchase one ticket per submission.

If you need further assistance, please let us know.
Regards.