Just a quick note to say, don't ever even think of buying anything from the XKCD store.
16 July: placed order on behalf of myself and several friends, and forked over £61 via PayPal. Warned shipping might take 5-7 weeks
16 September: no sign of anything. Chased by e-mail.
18 September: reply apologising and saying my order must be lost in the post by now. No online tracking? No way of chasing it? Seriously? In fairness, they offered me a replacement or a full refund, and I replied saying I'd take the refund.
3 October (after chasing several times!) - refund issued. I lost £2 to the exchange rate and two months' interest on my money.
XKCD may be a good laugh, but its store seems to be a joke, and not the funny sort at that.