Today’s Big Deal at Kindle UK is all seven Lisbeth Salander books (Millennium series) for £0.99 each. Note that the first three books (much nominated/awarded for various awards) are by Stieg Larsson, the next three by David Lagercrantz, and the most recent one is by Karen Smirnoff. All are price-matched at Kobo UK as well.
Links to: Kindle UK Big Deal page | Kobo UK series page (with a couple of strays in the middle)