ribs for 100

our annual bbq is coming up. they wanted to ad ribs to the menu. were also having hot dogs, hamburgers, saus & peppers, etc. how many slabs should cover this many people with this other food? also there was talk of paying me to smoke the ribs. whats a good price?

Its just something to add to the menu. I'm sure not everyone will eat them. guessing maybe 60 people plus were going to place them at the end of the food line so there plates should be some what full and maybe enough room for one to try and if they like them to go for seconds after everyone had eaten.