Where might you find sisal?

I'm not sure if this is where best to start this thread, but I want to make a combo scratching post and gym-condo. So far, I've managed to find several sites with plans and instructions.

Many of the plans suggest wrapping posts with sisal, but I don't know what kind of store might carry sisal. Can someone give me some ideas?

I've seen it sold at pet supply stores, and on pet supply websites here (Europe). You might even find it at home improvement stores.

I've seen it at Wal-mart before, in the hardware section, so I would be surprised if home improvement stores didn't have it too. Good luck!

I've seen it at Home Depot, Lowes, Truesource Hardware, dollar stores, Target....it's usually sold with the rope. I like the 3/8" thickness the best for cat trees.