I've been doing a lot of winter camping trips lately (snow storms and all) and have been building shelters / crashing in caves and what not. However I'd really like some kinda light shelter to carry with me that could fit two people but don't have $400 for an all season tent. I've been thinking about rigging something outta tyvek and a tarp, but aren't really sure if those are the best materials to use. Anyone got any suggestions?? My budget is extremely limited btw.