Instore at Topshop they have an extra 20% off sale prices, which are already up to 70% off. It says off 'selected items' but everything I bought discounted by an extra 20% at the till. My 10% student discount also worked on top.
I got 2 bikinis for £4 (originally £26), mom jeans down from £42 to £7, a hat down from £12 to £1.40, and a few other bits. Lots of stock in Preston.