Nice input and suggestions on the yarns..
In my experience, cotton and hemp tend to stretch and don't bounce back to shape well, which results in hats becoming unshapely pretty quickly.
I just bought some locally spun, hand dyed wool, which is just beautiful, but pricey, at $33.00 per skein. Takes almost a full skein per hat. Between 3 and 4 hrs to make the hat....how much can I realistically charge for a beanie? Right now I buy quality yarn from a local store and keep my materials cost between 10.00 and 15.00 each. If there is a market for higher end hats, I'd love to make more of those. For now, just ask me exactly what you would like,I'll tell you what I can do and it's a custom project, for each customer, as far as the priciest goods.