eBay or Amazon, I got my few pads of Muji from Stealth vape
Found you can order direct from muji themselves.
140 sheets of the stuff for £4.90 delivered. (seems like it's posted in the UK as well).
Let's see what 140 sheets of muji looks like:
This looks like a lot of cotton so does anyone fancy going in on this with me for £1 or £2 or whatever and I can send on however much to you?
I haven't tried Koh Gen Do ... cotton but I find this stuff outperforms rayon and that other random ... cotton I have.