You don't have to break the bank on entertainment, especially as a new event. The key however is to have something that is entertaining and memorable. Stay within your budget and do your research...there may be local talented artists with low costs that are hungry to perform.
When booking hosts or speakers, do it first thing as it usually takes some time to solidify your lineup. Ensure that once booked, they have a detailed plan of what you expect from them and know when to arrive and be ready for the event.
Target hosts and speakers that have a connection with your event. If it is a sporting event you are planning, look to the local pro sports teams for some help. If you are hosting a tech conference, seek out local start up success companies that might be a good fit to present the awards or emcee.