going to buy the derminator 2, how many cartridges should I buy with it?

[Giga Mogger]

title

 

[Mr.Proper]

Can't comment on cartridges, but a friend stocked them up just in case, after seeing how autistic and narcissistic the creator of device is (larping as multiple people/company, treating to sue people if they try to get refund or msking negative reviews). Who knows what's on his mind. Device itself is fine, though.
I'm thinking of buying some alternative.