GoBros[gobros.com] has a pretty awesome sock sale going on right now. At least 17% off with code ECLIPSE17. Free shipping on all orders. Edit: Code ECLIPSE17 is now expired. The smartwool socks code is still valid though
Their big DT sale is 20% off. So this is just about as good as it gets.
SmartWool is 20% off with code TREAT20.
GoBros sells many other brands of premium socks, too.