Any photographer can do headshots, but I suggest you get them done in one of the major filming areas. For example, New York City, Los Angeles, Chicago, Orlando, Dallas, or Philadelphia. If you live near any of these places, I suggest you go there to get your headshots done. The photographers in the areas where filming is done know what the agents and casting directors want to see because they work with them every day of the year. The price of a headshot session depends on the photographer and the package.
Most photographer offer their customers a package deal.
All photographers packages are different. You will want to make sure that the package includes a money back guarantee also in case you are not happy with your photos. Most offer a money back guarantee, some do not. Make sure you know ahead of time what the policy is. Like I said, it all depends on the package.