Devine,
I'm confused. You will set up, serve, and clean up but you do not provide the food?
To me, serving is part and parcel of catering, which includes all aspects of food service and may include event planning and decoration as well. I'm not familiar with serving being a separate function that gets charged separately.
In any case, figure out ALL your costs, both overhead (i.e. insurance, license(s), rent, etc.) and operations (i.e. labor, rentals, supplies, etc.), add your desired profit/income, and you have the MINIMUM you have to charge to avoid losing money.
Think $$$/event, not $/person, once you KNOW the event costs, you can easily calculate the $/person. Run the numbers, it costs far more in $/person for small events than it does for large events. Example: say your overhead amounts to, oh, $2000/month and you do 10 events per month. Your overhead per event is $200. For 20 people, that is $10/person just for overhead, for 200 people, it is $1/person, a BIG difference!
Operations WILL be fairly constant for parties greater than, say, 50 people. From my experience in my area, some rules of thumb (and they vary with the size of the thumb 
):
- Table setting rentals, from $4.50 to $10.00 per person and up (includes table covering, table settings)
- Tables and chairs, varies widely, probably starts around $3.00 and can go up to or beyond $8.00 per person
- Buffet rentals, wide variation
Unless you know YOUR costs, you will either charge too much and get no business or you will charge too little and will go broke.
KNOW ALL YOUR COSTS BEFORE TRYING TO FIGURE OUT YOUR PRICING!!!
Know what your competition is charging before figuring out your pricing!
