If you can’t spend much, your best bet is this Only Denim Shirt. It's a fantastic product, while not very expensive. Another strong contender for your wardrobe is this Lee Denim Shirt. While the price of this product is rather reasonable, it will definitely attract a lot of attention. You may also want to look at this Weekday Denim Shirt. This item is not expensive either, but it will make a difference in your wardrobe.
If you're a bargain hunter, check out this Denim Shirt. While the price is very reasonable, this item is an easy wardrobe update.