It’s technically “illegal” to sell any 
ecig related stuff on eBay.  All the checking is done with bots though so it’s not terribly effective.  There’s probably a specific methodology for avoiding them considering how much of it there is there.
Possibly a not terribly intuitive one.  eBay needs to up their game.  They don’t seem terribly interested in doing so though.  Probably make a lot of money off it.
 It’s become a primary way for shanzhai companies and various other shady operators to move counterfeit garbage into the US and to sell to minors.
I personally wouldn’t 
buy any 
ecig stuff off eBay myself if I had any choice whatsoever.