Two IF statements in a OnGUI function problem

Your 'if' structure here is wrong (commented out code) . Plus nested 'if(GUI.Button())' statements don't work. GUI.Button() only returns true for a single frame, so there is no way to see or interact with nested calls. You could use GUI.RepeateButton(), but you could never use the nested buttons because the moment you lift your button to press on the new buttons, they would disappear. You can have multiple 'if (GUI.Button())' statements at the top level. In order to sort these kinds of problems out, I recommend always using brackets '{}' for every 'if' and 'else' statement. Here is your code edited so that it will compile:

 #pragma strict
  
 var triggered: boolean;
 var width  = Screen.width /2 - 100;
 var height = Screen.height / 2 - 125 ;
 var store : boolean;
  
 function OnTriggerEnter() {
  
     triggered = true;
  
 }
  
 function OnTriggerExit(){
  
     triggered = false;
     store = false;
 }
  
 function OnGUI() {
  
     if (triggered) {
          var textWidth = Screen.width / 2 - 75;
          var textHeight = Screen.height / 2 - 10;
  
          GUI.Label (Rect (textWidth, textHeight, 150, 20), "(E) Enter Store");
  
     }
     if (store) {
       triggered = false;
       
        GUI.Box(Rect(width, height, 200, 250), "What do you need?");
        
        if (GUI.Button(Rect(width + 50,height + 90,100,30),"Buy Store")) {
              //This will disable the store menu and produce the buy or offer menu to buy the store
        }
             
        if (GUI.Button(Rect(width + 50,height + 120,100,30),"Apply for Work")) {
           //this will disable the store menu and produce the application menu for work
        }
         
        if (GUI.Button(Rect(width + 50,height + 150,100,30),"Shop for Items")) {
           //This will disable the store menu and produce the shopping menu
        }
       
        if (GUI.Button(Rect(width + 50,height + 180,100,30),"Nevermind")) {
               //this will diable the store menu and allow the player to move
        }
      
     }
 }
  
 function Update(){
  
     if(triggered && Input.GetButtonUp ("e")){
        store = true;
     }
  
 }