Here's the link.
Northern Tool

The fabric of the ones I have appears to be an 8x8 weave, but I'm not sure of the thickness. If we take it as a given that a 9x12 tarp contains approximately 12 square yards of fabric, then this fabric would be about 1.8 oz/yd to make a 1 lb., 6 oz. tarp. It's actually probably a bit less than that, because that weight includes the packaging, the rope in the hems, and the grommets, so it's probably about 1.5 oz/yd in reality.

The Equinox tarps are nice, I'm sure, but seriously...$42.99 or $99.99 for a 10x12 tarp is outrageous to say the least. These green tarps I got from REI were way expensive for what they were (I don't remember exactly how much, but $10-15 a piece sounds familiar) in the first place, and I wouldn't have even bought them if I could find anything remotely in the same weight category for that price.

The economy green tarps from Tarpaflex, as linked above, are probably the closest thing yet, at 2.7 oz/yd. Still, that would make them about 2+ lbs @ 9x12.

I've read mixed reviews but the common concencus seems to be it's about what you'd expect for $30, and probably well worth it. I might try one myself.