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If you're looking for a tarp, I got this one from Amazon and can't be happier with it. A bit more expensive than $10 bucks, but also not ridiculous. Plus the company sells them in a few different shapes so you can definitely find one that works.
Yeah, here's the $30 hex tarp I have if it's relevant (I don't like large tarps): http://www.amazon.com/gp/product/B00FB7XYXM
No doors, no frills, I don't use the included rigging, moderate weight, not long enough for my hammock if I don't rig up slack, and it's one of the largest things that goes into my pack. But it cost me $30.
UST base hex. Light, extremely durable and waterproof.
If you're on a budget, you could look into this. I picked one up a a few months back, though I haven't had the chance to try it out yet.
Here you go...its this one. Very useful in my experiences: http://www.amazon.com/Ultimate-Survival-Technologies-BASE-Orange/dp/B00FB7XYXM/ref=sr_1_10?ie=UTF8&qid=1428810351&sr=8-10&keywords=emergency+blanket+tarp