How can I mark an item SOLD automatically when it sells?

I made a form and used Paypal payment options. They are time slots for mini sessions, so obviously there can only be one sold.  Will it mark as sold once paid for?

Though it is not currently possible to limit product quantities in the payment field, the following thread describes how to set up limited quantities using one of our widgets to manage the available quantities:

https://www.jotform.com/answers/777857-how-to-limit-number-of-products-bought

With that setup, if you set the quantity available to 1, when the session is selected and paid for, it will no longer be available.