Well, basically the socks are already knit for you so I think the winning bidder took into account the value of a handknit pair of socks rather than the yarn they were made from.
I can usually knit a pair of socks in fingering weight in my free time
in about two weeks, so if you look at the time spent making a handcrafted pair of socks and put a value on that time/skilled labor that went into them then I feel the price would be appropriate, at least for the one willing to pay it. Aren't you worth at least $20.00 a week? I bet you are!
I am from that old school that always looked at a nice item and thought to myself, "hey I could do that" and then did it myself or just kept thinking about doing it myself until I lost interest :D