Question 2 - Choice - Pre Event or Post Event (user selects which one they are completing)
Question 3 - Text - Coke Stock - 10
Question 4 - Text - Sprite Stock - 8
And so on
Then the user fills the same form out again at the end of the event, with everything being filled out and Question 2 being selected as Post Event. If your event name or code is unique and the person completing it is unique, you could do something with the results to add to your SharePoint list.