If you are on a limited budget, your best bet is this Saks Fifth Avenue Knitted Hat. It's a wonderful item, while not very expensive. Another strong contender for your wardrobe is this Jocelyn Beanie. While the price of this item is not very high, it will surely attract a lot of attention. You may also want to look at this Beanie. This item is not expensive either, but it will make a difference in your wardrobe.
If you're looking for something in between pricewise, look no further than this Yves Salomon Beanie. This item doesn't cost a fortune, but absolutely indispensable in your wardrobe.