35 Year Class Reunion- How much do I charge?

I have been approached to take photos for 35-year class reunion.
They want on-site printing.
What is a fair price for 8 x 10 or a 5 x 7 print?

Thanks in advance
Eric

Two ways to approach. Flat fee for the night that includes all time and prints that can be produced in the time frame or spec.

I'd prefer the first to the second. You should know how many pics you can produce an hour, plus your time, therefore you should be able to calculate your cost.

Spec work is either GREAT or a dud. At my 30 year reunion, everyone had a camera and I can guarantee that they shared the images. Spec would have been a waste of time. Even if 20-25% of the people bought images, there would have been a tremendous loss in terms of labor... Just not worth it.