Replying to Crochet Hats

So I've been selling crocheted hats at my high school for 3 years now. I used to use cheap acrylic yarn and a fatty hook so it took about an hour and i charged like 12 bucks for a crap product. This year I'm using much higher quality yarn ($4.50 a roll) and making way cleaner stitches so the hats are softer, warmer, and pretty high quality. My question now is what do YOU think is a fair price for hats (earflap, beanies, condom hats, etc..) I've been hearing $18 is a fair price. Any help/suggestions are super appreciated.