Check ebay often for a Mountain Hardwear Micromesh Bivy. It's about one third skeeter netting on the top and a taffeta type fabric from the waist down with waterproof bottom. When they show up they're "cheap" and all one needs under a tarp to keep the bedroll together and the bugs out.
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...ask for the old paths, where is the good way, and walk therein... (Jeremiah)