There may be cases where your Event doesn't have a billing contact. If this is true, you'll see something like this when looking at your Event Overview page:
Notice the Blue Button labeled Configure Billing Contact. This button will guide you to our Event Billing Settings Page. Here you can configure a Billing Contact.
What is a Billing Contact? This person is responsible for all charges associated with this Event. This person will be sent both Pre-Paid and Post-Paid invoices generated for this Event.
To configure the Billing Contact for this Event, click on the dropdown highlighted in the image above. You should see a list of users associated with your account. Pick the appropriate user here and click the Save Changes button to persist your choice.
After this is complete, you can now Add Media Budget to your Event!