Yeah, I was paying $7.50 for shipping, too. I thought it was a little much, but it was the best deal I could find at the time.
I found that I needed 2 applications for my Mazda Protege5 and 2 for my wife's Pontiac Bonneville. If you had something like a Suburban, boy, you might need a few. 2 applications lets me do all the windows and the two side mirrors once. That's after cleaning the windows with vinegar and water. They were clayed at the beginning of November.
There was someone on here who was able to do all his windows once, plus his winshield twice, with one applicator. I think that was after glass polish, claying, etc. Just follow the instructions, it's pretty easy. Sure beats Rain-X. I had some wiper chatter on my windshield for a few days, but it went away and hasn't been back since.