I have a simple tarp, 5x9' made of lightweight ripstop waterproof material from Rockywood fabrics.
Constructed a wall tent (w/ MIL assist) using a similar fabric as shared below though my fabric was around 3oz per SQ yard. 15#'s with titanium lg SO stove/pipe.
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They're a wholesaler for public materials. It's like entering a steel yard... Haha! I want to buy too much as the creative juices kick in. Everything from linear yardage ripstop to snaps/clips, zippers, webbing, etc.
www.rockywoods.com
One example: 0.68oz per SQ yard.
7D Ultralight Coated Ripstop Nylon Fabric
www.rockywoods.com
Also have an "Outdoor Research bivy-sack helium bivy".
1#. Packs to 1'x4" and carry it when my intent is to spike camp with sleeping bag though I've carried it with my reactor extreme on occasions where I sensed bad weather may hit.
I've seen them new for as low as $140.