I know amazon has large packs of like 100 sheets of Japanese cotton for like 30$ or less. As for cotton bacon v2 I've always got it from my local vape shop for like 10$ or so a bag.
As for which is better that more of a personal preference.
I use Salon Coil Cotton from Sally Beauty supply. 40 ft or so for under $4.
Been using one box for 2 years and am a bit over half done with it.
It is not the Rayon stuff.
Is very much like cotton bacon. Might be the same stuff for all I know.
I just bought cotton bacon for the first time yesturday and I been vaping for a long time. There is great flavor with it. But Japanese cotton is good too.