Have you seen these awesome Socks With Capes? They have popped up on the likes of Amazon and eBay before, but this is a much better offer than I have ever seen for them. To tie in with the new Batman v Superman film you can get a Buy One Get One Half Price at Sock Shop, and with prices from £4.99 a pair that's by far the best offer around.
There are both Batman and Superman styles for kids (it says boys but of course girls can wear them too), as well as mens and ladies, so the whole family can choose their favourite superhero.
You just add two pairs to your basket and the second pair will automatically be adjusted to half price. Home delivery is a bargain £1.25 as well so you are getting a super price here for some super cool pairs of socks.
If you see anything else you like, or want to kit out the whole family then you also get a free gift worth up to £4.99 when you spend £25, and you get to choose from a selection.
I'd be tempted to get a pair of each and wear one Supes and one Batman at a time, but then I am a bit geeky (and I may or may not do that with my Iron Man and Captain America socks already).