Black Caps from Amazon.com
If you're a frugal shopper, your best bet is this Steve Madden Cap. It's a great piece, while not very pricey. Why not also check out this Keds Cap. It's an item you'll fall in love with which also doesn't cost a fortune. You might also want to consider this San Diego Hat Company Baseball Cap. The price is very reasonable, but the effect on your wardrobe will be pretty fantastic.
For something in the middle of the price range, we've got your back with this BCBGeneration Cap. This item is bound to become a total wardrobe staple.