Iron Heart, Empty Wallet

I ride mostly in jeans but decided I could use something tougher than my standard 501s. I've pretty much narrowed it down to the Asphalt jeans from Deth killers but decided maybe i'd try a pair of Iron hearts first. Although all cotton they are 21oz denim and said to be pretty damn durable. Thing is last time I checked they were a a few bucks north of $200 and suddenly a few months later you can't touch a pair for less than $350! What the hell guys? You do know Cotton grows right out of the ground right?