The one you're looking for is the On Field knit. I was looking for one to wear at the New England game, and came across the one on Amazon that's currently going for $74 (http://www.amazon.com/gp/product/B00MYHN798/ref=gno_cart_title_0?ie=UTF8&psc=1&smid=AMOD330W75U7I). When I found it, it was $35, but wouldn't have shipped in time for the game. My best advise would be to keep checking that link as it may go down.
The Pro Shop one for $15 is different than the one you want. I have the green and gold On Field knit, along with the $15 version from the Pro Shop. The cheaper one is much thinner, but still a solid cap. Hope that helps!