I can't recomend the
pearl dr-80 enough. It's the cheapest rack on the market, The clamps don't slip due to square tubing and at the end of the show you just fold it up.
I used to own a gibralter. It was heavy, and you had to pull the whole thing apart after the show not to mention brake your hands doing up the clamps so they wouldn't slip, I actually broke a couple of clamps.
I got the dr-80 three years ago and its taken quite a beating thus far with no complaints. I'll get an icon when I have roadies to set it up for me.
Bear in mind any rack you buy will require more hardware once you start setting it up, but once you've got your hardware together you'll be happy as a pig in poop.