I actually use a tarptent, or a remaindered 9x9 REI tarp that cost me $24.93, but a friend likes the Kelty Noah tarp of the same size, currently ~$60. Its sturdy, and has grommets and tie out lines built in, and can set up to keep a bunch of us out of the rain at camp time. Very versatile, and not as pricey as silnylon, but not as light either. I say any port in a storm, I have several tents set by for emergency shelter, but as long as the grommets are sturdy I keep a couple general purpose tarps and some paracord in my emergency supplies. If not for me for my neighbor.