Buying a Nightfall code not in the Anet store

So I've been wondering if there are any sites that just sell codes for Nightfall but at the reasonable price of $20 (Which is Amazon's price for the dvd-rom itself). I'd like to not have to wait on shipping if I could just buy a code and stream the content as I go and have instant access...but that's not worth the $50 gouge from the Anet store. Thanks!

You could probably find NF for cheaper than $40 in a brick and mortar store. But ideally if you're looking for the $20 price point, get it from Amazon.

I bought Nightfall for $16 at Circuit City in Arizona.