Unity, PlayerPref saving array of item

Ok, say I want to buy a lot of item and save it into the PlayerPref, how should i do it???

var totalitem: int;

//so first i try to get the totalitem from the player pref "totalitem" at first it will return 0 as there are nothing inside

totalitem = PlayerPref.GetInt("totalitem");

//then, say i click buy item 1, so i save the item 1 into player pref "item1"
PlayerPrefs.SetInt("item"+totalitem, 1);
totalitem+=1;

//if i click multiple time buy item1, it will then save item 1 into "item0", "item1","item2"

PlayerPrefs.SetInt("totalitem",totalitem);            

//EXAMPLE LET SAY I CLICK BUY ITEM "1" for 4 times, it will save it inside playerpref as below
//totalitem=4
//item1=1,item2=1,item3=1,item4=1


//SAVING IS DONE


Now I want to do the loading, I need to load the stuff back into the selling screen, since i only save number "1" in the "item1", "item2", "item3", i can load it back as below

var myitem: ArrayList;

function Start () 
{
    myitem=new ArrayList();
    totalitem=PlayerPrefs.GetInt("totalitem");

    for( i=0 ; i < totalitem ; i++)
    {
        myitem.Add(PlayerPrefs.GetInt("item"+i));
    }

}

 GUI.Label(new Rect(50,100,100,100),"My Item: "+myitem[0]);
 GUI.Label(new Rect(50,170,100,100),"My Item: "+myitem[1]);
 GUI.Label(new Rect(50,240,100,100),"My Item: "+myitem[2]);
 GUI.Label(new Rect(50,310,100,100),"My Item: "+myitem[3]);