Is it allowed?

I'm waiting for answers like : yes or no . I won't answer any other questions.

Is it allowed to sell item create method on black market?

If its a tutorial, them no.

It shouldn't be either. That would totally ruin the game.

dont worry, nexon is already ruining the game. so he might aswell simply release it and it wont change much.

no, it is not.

not at all.