If you're budget-restricted, your best bet is this Beanie Hat. It's a popular product, while not very costly. Another nice option is this Saks Fifth Avenue Beanie. While the price is not very high, be sure that this piece will become a worthy addition to your wardrobe. You might also want to consider this American Apparel Beanie Hat. The price is very reasonable, but the effect on your wardrobe will be pretty fantastic.
If you want to splurge on a luxury piece, then you won't be disappointed if you check out this Eugenia Kim Knitted Hat. It's a costly but smart option. Why not take a look at this Hat too? Expensive, but worth every penny. And how about the luxurious Thom Browne Beanie? Yolo, right?