I did some comparison shopping a few years ago and ended up using Claire Folger (
http://www.clairephoto.com). Her studio is/was in Cambridge near Inman Square. Not only was she less expensive than the others I interviewed, she made better use of both studio and natural light, and her work had an artistic quality the others lacked. She's flexible about how many reels you want to take, etc., and she can provide digital copy along with the prints.
If you're looking for a dirt-cheap route you can go to a Sears photo studio or someplace like that, but they don't specialize in actor headshots.
