Dispoable Backpacking Gear?

I once paid $20 for what was essentially a plastic bivy sack. To my surprize, I was relatively dry after an all night rain. The problem of condesation may be over-rated, I decided. So I made a bivy sack from two garbage bags duct-taped together. It weighed 4 ounces, and was 3’x7′. It fit in my pocket, and left me only a little damp in the morning (don’t breath inside it). I hit the trail and was dry in a few minutes. This type of bivy is best for a dry climate, but I haven’t had any real problems yet. Any other cheap, light gear ideas out there?