The main thing is that GoingGear.com offers free shipping on orders over like $40 or $50, can't recall the exact amount. It even applies to the PP. Since that has to ship Ground, I've found with most eBay sellers that the shipping is more than the product. Overall it's still cheaper per gram but who needs 5 lbs of the stuff? I agree that the 'steel is about the best fire tool out there but the PP would be a nice backup, especially where dry tinder is an issue.
BTW, I had a really surprising cotton ball failure while camping last week. I tried a new method of dipping them in a pan of melted wax instead of dribbling wax over them. As it turns out, that batch had too much wax too far into the ball. I guess I shouldn't say it "failed"; it did take a spark and burned enough to get my kindling lit. But then the cotton ball went out!

I was pretty shocked- I've never seen that happen. But in looking at that batch they felt like pure wax. I needed a knife to open one! But hey, that's why I was using them in a State Park, and why I had half a dozen tried 'n' true tools with me. You don't learn without trying out new stuff but you don't want to learn in a situation where the lesson can kill you, either. I've had great luck with waxed balls, but I will have to go back to my old method of making them.