Hi,
I just ordered two duvet cover sets (single duvet and pillowcase) for a grand total of £9 as item is on sale and it's BOGOF. Also, if you click on 'collect +', it gets delivered to a shop very near to you and delivery is free then! Here are some of the bargains I've found. BTW, I bought the dinosaurs one as have two DSs.
Dinosaurs - BOGOF and sale price so £9 for 2 sets
Flower set - BOGOF so £10.50 for 2 sets
Stars and Stripes - BOGOF so £10.50 for 2 sets
Other duvets sets on sale from £4. And if you use Quidco, you get 6% cashback too. :)