I know that it was 0-50hd. I think if it should be implemented it should be 2 options when you duel with the opponent.
1: Normal duel> Choose amount of Pokes>start duel.
2: Duel with bets (where one of the players chooses the amount, and both has to agree it by clicking yes or no, when example this message appears) "player xxx has invited you to duel with bet (50hd), do you want to accept?" Then click "yes" or "no". If yes..>Start duel>Winner gets the cash automatically from the other players backpack/locker. (Both of the players need the amount of cash in the Locker or Backpack).
Then it sounds great