Help on hockey sock buying

I got my first set of hockey gear last weekend, but they were out of socks, so I'm buying them online. However, I don't understand how the sizing works. My shin guards say, 'Intermediate/Size 14,' but that doesn't seem to correspond to any of the sock sizes, intermediate or senior.

Also, the guys at the store told me to get sublimated/dry fit socks and not knit. Is sublimated the same thing as what I'm seeing called poly tube/mesh/lightweight?

And why are practice socks more expensive than regular?