Each state has its own laws regarding ticket resale. Some states prohibit tickets being resold for more than face value. Other states allow tickets to be resold, but only with a certain dollar amount or percentage above the face value. There are also states that allow the resale of tickets at any price.
Although states have laws to regulate the resale of tickets, they are not in effect when the buyer and seller are outside of the state where the event is taking place. Ticket brokers from a neighboring state may purchase tickets to an event and then resell them with no limit.
Outside of state law, the original seller of the tickets may have its own policies regarding the resale of tickets. Artist fan clubs, such as that of Dave Matthews Band, ban the resale of their tickets above face value, regardless of the law, and threaten to revoke memberships if caught.