This is very low, consider yourself lucky

. did you mean $5k-10k instead - because that what I could see it costing.
I cater my 4th of July party, italian beef, sausage, pasta and fried chicken for about 70 people and its close to $500 and THAT'S cheap.
You will never ever feed 100 people anything in a hotel for $500. That's what some hotels charge for a cup of coffee.
ETA: I meant a cup of coffee for each guest....not one cup