Home Depot sells it in 100' bundles 1/2 in. x 100 ft. Assorted Color Diamond Braid Polypropylene Heavy Duty RopeIt really does handle like a polyester double braid. I have been using it for 12 years or so and the stuff holds up.

I don't think this is true double braid as the inner core is not braided.
I use it for work rope to haul stuff (satellite dishes, cinder blocks, etc.) up onto roofs, and as the pull line on my extension ladders. Much better hand feel and knot holding than regular poly triple braid.