Whats the max zeni that a char can hold?

1,000,000,000

1kkk or 1kkkk? i know that in trade is 1kkk, but i mean in your eventory, your normal money...

1KKK is max in inventory. Once you have this in your inventory you can no longer get any zeni until you either spend it or send it to another character. Guild bank can hold 2KKK.

KKK means Billion or Klu Klux Klan

KKKK would be a Trillion