The Knitting Network have offers on a selection of DK weight yarns including West Yorkshire Spinners Bluefaced Leicester DK which is half price at £2.49 per 50g ball and Stylecraft Moonbeam now £1.35 per 50g ball.
There are knitting patterns available for the West Yorkshire Spinners Bluefaced Leicester DK yarn at £1 each. You can find all their sale yarns including the DK offers here.
This page includes affiliate links, if you follow them to shop it wont cost you any more but I may receive a small commission which goes towards the running costs of Pollyknitter.