If you're after a thrifty option, your best bet is this Asos Bandana. It's a popular product, while not very pricey. Another strong contender for your wardrobe is this Asos Baseball Cap. While the price of this piece is competitive, it will definitely attract a lot of attention.
If you're looking for a good deal, look no further than this Asos Beanie. This item doesn't cost too much, but definitely deserves a place in your wardrobe. It's also worth taking a look at this Asos Cap. This item is ultra popular and, just as importantly, not very expensive.