I've seen the Huofist neckseals on ebay going for $30+ and so forth. I was at Wal-Mart and experienced a mini-epiphany.
As I've mentioned before I'm building a 'b' suit to finance my 'a' suit and needed a makeshift neck seal. Well I bought a xxxl white t-shirt for $4 and I cut out the sleeve with some extra flap and it works and looks just fine to me. It's quite comfortable, not stiff, and can be lifted to cover the entire bottom of your head, right out to your chin. I don't have any pictures but when things start to be finished better I'll try to post pics.
Felt like an idiot standing in wal-mart trying to shove my head through a shirt sleeve