I just picked some up on ebay. 3.99 for 6 feet. And a fellow vapor bought a box of 500ft and is sending me a bunch for free. First of all, I have to say the flavor is out of this world. It also has been instrumental in getting my authentic Squape to work flawlessly. I had so many problems getting the cotton just right...too much and it would burn, too little and it would leak. I went to adding a flavor wick, but after a half a tank it would still leak.
Learning that you could really cram the cellucotton into a coil and not worry about burn, I loaded my coil up tight (not so tight you have to fight with it) and it's been AMAZING. No leaking, best flavor.
I have tons of organic cotton in raw and wick form. It's going to get used anyway for certain builds. I prefer the cotton for my nimbus and I like the braided wick for threading into my origen v2, but I will be using the cellucotton for all my other builds until the cotton is all used up (100 years from now). LOL.
As for safety, some say yes some say no but the way I see it is, I absolutely won't use silica because I got some of those threads in my throat once and it was pure hell. So it's got to be safer than that.