I just realized, thanks to an LYS, that a Tardis-themed knitted shawl exists right here for free:
The yarn suggested takes slightly more than one skein and costs $26.50 per skein, leaving you with enough left over to make a pair of socks!
Too much, although lovely stuff.
WEBS (www.yarn.com) to the rescue! On their site, I found Cascade 220 Sport in the perfect blue for (are you ready?) $5 per 220 yard skein.
For $18.50 (includes shipping), I get 3 skeins. Twin gets the shawl of her Whovian dreams!