selling prints @ a showing?

I am working out details of being "artisit" of the month at a local outdoor store. I am showing some prints on one wall of the store ( maybe 10, 8x10's. 2, 18x24) and I am asked to be at the showing on a saturday for a few hours.
I was wondering if it was tacky to try and sell prints during that time and if not how do I approach this with the store? Should I offer a % of the sales as an incentive to allow me to sell the prints?
I will be meeting with teh store mgr this next week or so to hammer out details and want to be preped for stuff. any advice is awesome.
Thanks

For the showing, you might consider a “work of visual art” (2) as defined in US Title 17 § 101 Definitions. Local gallery owners might discuss commission arrangements with you.

What about using a laptop or digital frame to slideshow through a sample of your second best photos?

Thanks for the input!