Generic tickets are worth $2 and can be used to pay for any event at Gen Con, as long as that event has space for more players. You simply need to provide enough generic tickets to equal the registration cost for the event.
Generic tickets can only be refunded for system credit. There is no cash refund on generic tickets. (System credit can be used to purchase future badges or tickets. It is non-transferrable, non-refundable and does not expire.)
The maximum number of generic tickets that can be purchased for any one person is 200.