Free: Contests & Raffles.
I have the OR Crocodile gaiters that are bulletproof but loud. I got a set of Kenetrek's and second the quietness. The material strength wouldn't compare to OR, but it's a trade off.
I have the OR Crocs and a pair of the Cabelas extreme something or others. They work well and are relatively quiet. The Crocs are totally bombproof but are noisy in the brush. I wear gaiters 90% of the time.