I have one I got from costco. Like previous post it can lay flat and roll with four wheels if necessary. Made from mostly aluminum so it's relatively light, and won't rust. It has big tires, rolls well, but I don't know if they are flat free. It's a little bulkier than some, but seems pretty well-made. I think it was like $80, a little spendy but after using it a few times, I don't mind.
