Don't try to sneak in - if you really don't have the money, find the organizer and privately explain the situation, explain why you want to be there, and ask if

Don't try to sneak in - if you really don't have the money, find the organizer and privately explain the situation, explain why you want to be there, and ask if there is anything you can volunteer for to help. If you try to scam them you'll lose your reputation along with getting kicked out - if you approach it eagerly and ready to work to gain that experience you'll leave with a new contact and the experience.