What is the process involved for booking a Celebrity for a Special Event? And approximately how much do you pay to do this?

When you say "special event" is it a public or private event?

Typically the process goes like this:
1. Contact agent to check availability
2. Submit offer
3. Negotiate pricing
4. Contract and pay deposit

The pricing for the booking of a celebrity is going to vary based on many factors. if it is a private event, it will typically cost more than it would for a public event. You can get the pricing information by speaking with an agent, who will ask you to submit an offer.