If you can’t spend much, this Burton Beanie will fit the bill. It's a great choice, while not very pricey. You might also want to check out this Patagonia Beanie. It's an item you'll fall in love with which also won't break the bank. You might also want to consider this Neff Knitted Hat. The price is very reasonable, but the effect on your wardrobe will be pretty fantastic.
If you want to treat yourself, then you absolutely must check out this Danielapi Knitted Hat. This piece seems pricey, but it's worth it. Another product we're drooling over is this Marni Beanie. It's expensive but you get what you pay for.