Hats are a hard sell. Even to people who buy hats for advertisement purposes. I know a man who owns a livestock auction barn. I've tried selling hats to him but can't meet the price from where he buys them.
He gets hats for und $2 printed with 1 color design.
Many others livestock, feed companies, etc. give hats out for free for advertisements but many of them buy from the main company and can't buy from a local printer.
I live in rural Missouri and most everyone out here wears a cap or hat of some sort. Yet you can't hardly sell hats to them. Mostly because they get free ones from businesses who buys from the main company.... Do you see why hats can be a hard sell?
But, like has been said, there is some good money in hats, it's just harder to get business with them.
Best of luck!