Is $600 including cleanup fee, too much for a caterer that will be feeding 50-75 people a buffet style dinner?

Okay, I found this lady and her husband listed in my local phone book. They seem professional enough, with business cards, and a mobile bbq pit they use if that is your choice. They also have a photo album that seems legit, it's full of photos from events they claimed to have catered to. Now she and her husband operate this business out of their home. Or to be more specific, a building on their property near their home. the building is ully equipped for what they are claiming to be doing, and that is a catering business. They have been in operation for 3 years and claim to have catered 100 events during this time. She and her husband are asking for 600 to feed a guest list of 50-75 folks. The menu will be a homestyle country type buffet meal which will include fried chicken, homemade mac ''n" cheese, collard greens, green beans, baked chicken, ham, ribs, rolls, biscuits and for dessert, bananna pudding, jello, and my choice of 3 cakes. They will also be serving tea, lemonade and wedding punch. She is saying 500 for the food, and asking an additonal 100 for cleanup. I already have in mind the place I want it, and this place is providing the linens, so in a sense, she is just cooking and setting up the food. Am I getting duped, and would you use this couple. They are not a part of the BBB, and even though they claim to have had this business for 3 years, none of my friends has ever heard of them. And if this helps, I went over to talk to them, and they were in the middle of cooking for a cl reunion. The food was smelling delicious, and she let me sample some, it was off the chain!