I’ve never had a school dance that sold tickets. For extra money we would do fundraisers BEFORE the dance to afford the decorations, DJ, etc. Then at the dance itself you could buy photos, snacks like cookies and brownies, and soft drinks. That way, any kid, regardless of income could attend as long as they were a student from the school. Selling tickets to the dance seems unfair as there may be some kids who can’t afford that and it’s embarrassing to be asked “are you going to the dance?” and having to make excuses why you can’t because you can’t afford a ticket.