If you're on a thrifty budget, your best bet is this BDG Beanie. It's a fantastic product, while not very pricey. In this price range, you can also consider this Urban Outfitters Knitted Hat. It's also a popular item and won't break the bank. You might also want to consider this Kimchi & Blue Hat. The price is very reasonable, but the effect on your wardrobe will be pretty fantastic.