I have event which would cost registrants $55 but they need to have the option if they want to invite additional people to the dinner or perhaps they want to buy a few more event shirts.
Each extra dinner is $10
Each extra shirts is $15
Plus the event registration for the participant is $55.
What is the best way to handle this type of event fees?
This would be easily done with custom fields. Watch our custom fields video tutorials... particulary the selection fields video and you'll see everything you need to accomplish this.