Building a Cash Register using JavaScript

Building a Cash Register
var cashRegister = {
    total: 0,
    add: function (itemCost)
    {
        this.total += itemCost;
    },
    scan: function (item, quantity)
    {
        switch(item)
        {
        case "pencil":
            this.add(0.98 * quantity);
            break;
        case "pen":
            this.add(1.23 * quantity);
            break;
        case "magazine":
            this.add(4.99 * quantity);
            break;
        case "eraser":
            this.add(0.45 * quantity);
            break;
        }
    }
    s
};
// scan each item 4 times
cashRegister.scan("pencil", 4);
cashRegister.scan("pen", 4);
cashRegister.scan("magazine", 4);
cashRegister.scan("eraser", 4);
//Show the total bill
console.log('Your bill is ' + cashRegister.total);
OUTPUT
Your bill is 30.6