For the entertainment for your event you can either book bands and acts yourself or turn to an agent. An agent will have a list of acts ready to work and can be a go between. The acts pay the agents so if booking is the only service provided there is no cost to the venue operator.
If you are doing concerts there will be an agent involved at some level. Some agents will provide more service such as on site coordination for a fee.
A promoter may become a limited partner. He will bring in usually a major act but he will need to make some money on ticket sales or a percentage of the bar, or both. Partnering with a promoter can allow a venue operator to provide entertainment that he might not consider if he was handling the whole transaction.
We are currently taking listings for agents and promoters. Contact us at firstname.lastname@example.org