How to have a gallery on budget?

[verdantsound]

My friend and I collaborated on a photography portrait project featuring students from our school, and we want to have an exhibition featuring the photos that we took. We will have about 100 12x18 prints, but the room that was given to us don't have walls we can use. What would be a cost effective way to display them? Also, where can I find/buy backing for those prints for cheap?

Our project is here: 99columbians.com

Thanks!

[Mark1]

What kind of ceiling is in the room? I have been to shows where the images were hung from the ceiling about 1.5 feet from the wall.