You can set a product to be automatically selected when a person answers a specific question on a form. This is by setting a "Trigger" against a product. The person is unable to remove that product from being selected.
Process to enable a trigger
Once a product has been added to the form you can then click the Trigger link.
A popup is displayed that allows you to setup the conditions you want met. You can now select the question you wish to check from the list provided in the "If" field, the answer you are checking for in the "is answered with" field, and the quantity increase in the "then increase item quantity by" field.
In the example below, we want to set a trigger on the question field Grade. If a person selects the grade Under 20 we want the Senior membership product (amount) for that grade to be automatically selected.
Click Save Trigger. You will now view the trigger set, Click +New Trigger to continue to add triggers for the other products. From here you can remove/modify existing checks by selecting the trash/pencil icons next to your triggers. You can add more than one trigger to the same product
Using the above example, registrants who have selected the Grade of Under 20, Premier Mens, or Women's will be required to pay for a senior membership.
Value not specified
If you do not need a specific answer to a question to trigger the automated purchase, the "is answered with" field should be left blank. The product will automatically be added if the question is answered.
For example, on a form there is a question "Member ID number" that is a SingleLine Text
The requirement is for the trigger to be invoked and a product added if a member ID number is entered into this field. When you click to set the trigger the "is answered with" option is set to value
This shows that if the question is answered add the product.