if you're in a thrifty mood, your best bet is this Topshop Beanie. It's a terrific piece, while not very pricey. In this price range, you can also look at this Hinge Beanie Hat. It's also a popular item and won't break the bank. Or you can choose this Beanie - be sure you'll be making a stylish addition to your wardrobe.
If you're looking for a bargain, consider this Helmut Lang Knitted Hat. While the price is very reasonable, this piece is an easy wardrobe update. You can also consider this Helmut Lang Hat. It's an attractive option both price and quality-wise.