[Lordzy]

pawn Код:

public OnPlayerEnterVehicle(playerid, vehicleid, ispassenger)
{
  if(GetPlayerState(playerid) == PLAYER_STATE_PASSENGER)
  {
   GivePlayerMoney(playerid,-12);
  }
  else if(GetPlayerState(playerid) == PLAYER_STATE_DRIVER)
  {
   GivePlayerMoney(playerid,12);
  }
  return 1;
}

NOT TESTED. But you dont need to loop.