Jeez, everyone has me blown out of the water with cost. Currently my most expensive cosplay is Oswin Oswald.
Socks (ended up having to buy another pair after buying the wrong color): $24
Hair Clips: $4
So, in total, about $160. It probably would have cost more, if I had tried to recreate her belt and watch more faithfully, instead of just borrowing my dad's web belt and watch (and my mom's sauce whisk!).
Not quite sure if I will beat this price anytime soon, but we'll see! (I'm starting to try and hunt down more SA Doctor Who pieces, but it's hard and expensive -_-)
-San Diego Comic Con 2013