Number once decrease

Hi, i am newbie, but have some experience, i am making some study expamples for me, i making money decreasing or increase when is the other number selected i already made number with random range when i press A the number change (0,10) and i make a money and when is the number one selected money decrease by hundred, but the hundred decrease per second of my money and i want make this when i press A the money will be decrease by hundred 1000-100=900 how can i make it ? there is the code:

 var number : int;
     var money: float;
      
      function Start() {
      number = Random.Range(1,10);
      money = 1000;
      }
      
      
      function Update() {
      if (Input.GetKeyDown(KeyCode.A)){
      number = Random.Range(1,10);
      }
     if (number == 1){
      money -= 100;
      }
      
      }
      
      function OnGUI() {
      GUI.Label(Rect(10,50,100,300), "Money: " + money);
      GUI.Label(Rect(10,10,100,300), "The number that was generated: " + number);
      if(number >=5){
      GUI.Label(Rect(180,10,100,300), "Bad");
      } else {
      GUI.Label(Rect(180,10,100,300), "Nice");
      }
      }