Flat Caps from Nasty Gal
If you're not planning on spending much, this Nasty Gal Newsboy Cap will fit the bill. It's a fail-safe choice, while not very expensive.
For something in the middle of the price range, we've got your back with this Nasty Gal Fisherman Cap. This product is likely to become a total wardrobe staple.
If you have enough to afford it, then what you're looking for is this Nasty Gal Flat Cap. It's more expensive but worth your money.