If statement only work once?

Hello I have a little trouble with my script, can someone please help me?

Here's the thing, when my "TEST2.js" earn some value on "money1" (still lower than the price), it works.

When I press the GUI in-game it wont add the amout of "hoverForce" and decrease the amout of "money1" and "money".

But after I bought the item +1 or +5 or +10 I can just buy it non-stop untill -1 and so on but I set it >(bigger) than the price value.

I don't know how to fix this because -(negative) is smaller than 0 :) i just don't get it with the logic

 TEST.js

 static var hoverForce : int = 0;
 static var thisisjustatest : int = 0;
 
 function OnTriggerStay (other : Collider)
 {
     other.rigidbody.AddForce(Vector3.up * hoverForce, ForceMode.Acceleration);
    
 }
 
 function OnGUI(){
 
 GUI.Label (Rect (100,100,50,20), thisisjustatest.ToString(), "box");
 
 }

                          TEST2.js

 static var money1 : float = 0;
 
 function OnGUI()
     {
     if(GUI.Button(Rect(200, 100, 40, 20), "+1")){
     if(money1 > 0.9)
     {
     TEST.thisisjustatest += 1;
     TEST.hoverForce += 1;
     TEST4.money -= 1;
     audio.Play();
     }
     }
     if(GUI.Button(Rect(240, 100, 40, 20), "+5")){
     if(money1 > 4.5)
     {
     TEST.thisisjustatest += 5;
     TEST.hoverForce += 5;
     audio.Play();
     }
     }
     if(GUI.Button(Rect(280, 100, 40, 20), "+10")){
     if(money1 > 9.9)
     {
     TEST.thisisjustatest += 10;
     TEST.hoverForce += 10;
     audio.Play();
     }
     }
     if(GUI.Button(Rect(200, 130, 40, 20), "-1")){
     TEST.thisisjustatest -= 1;
     TEST.hoverForce -= 1;
     audio.Play();
     }
     if(GUI.Button(Rect(240, 130, 40, 20), "-5")){
     TEST.thisisjustatest -= 5;
     TEST.hoverForce += 5;
     audio.Play();
     }
     if(GUI.Button(Rect(280, 130, 40, 20), "-10")){
     TEST.thisisjustatest -= 10;
     TEST.hoverForce += 10;
     audio.Play();
     }
 }
                          TEST3.js

 static var timer : float = 1;
 static var addtime : float = 1;
 
 function Update(){
   timer -= Time.deltaTime;
   if (timer < 0){
   TEST3.timer += addtime;
   TEST4.money += 0.5;
   TEST2.money1 += 0.5;
 }
 }
 
 function OnGUI(){
 
 GUI.Label (Rect (100,280,100,20), timer.ToString(), "box");
 
 }

                          TEST4.js

 static var money : float = 0;
 
 function OnGUI(){
 
 GUI.Label (Rect (100,300,50,20), money.ToString(), "box");
 
 }