Berets from TheRealReal
If you'd rather not spend much, your best bet is this LOLA Cosmetics Beret. It's a fantastic item, while not very costly. You might also want to consider this Sonia Rykiel Beret. It's a product you'll fall in love with which also doesn't cost a fortune. Or you can opt for this Kate Spade Beret. This item has all the potential to become a powerful player in your wardrobe.
If you're willing to splurge, then you won't be disappointed if you check out this Hermes Beret. It's an expensive but smart option.