If you're not planning on spending much, your best bet is this Rag & Bone Button-Front Shirt. It's a terrific product, while not very costly. Another strong contender for your wardrobe is this Oxford Shirt. While the price of this piece is not too high, it will certainly attract a lot of attention. You might also want to consider this Joseph Classic Shirt. The price is very reasonable, but the effect on your wardrobe will be pretty fantastic.