We did some pricing about 2 years ago from some of the local bbq places for catering and the LOWEST price was about $12.00 per person. Of course some of the more gormet type cooks that cooked everything offsite and dropped it off in their pans and let us serve was around $60.00 per person.
Most catering places charge by the person, and if you do a little research on the internet for catering in your area, you're bound to find someone that cooks similar to you and has prices posted.
I think that prices can be adjusted as you go along in your business... supply/demand type thing. If you are in high demand, you can up your prices... I personally wouldn't start out any lower than $12.00 per person for a couple of meats and a couple of sides.
Of course, I have NO practical experience in this area, as I've never acutally DONE a paid gig... But one day soon, hope to!