Popped into my local T K Maxx (Stafford) today and they had a load of different Ravensburger Jigsaws for £4.99.
There were quite a few to choose from so I'd imagine you could get some of these in other stores too. The ones in my store included:
Winnie The Pooh Campfire (£11.99 at Amazon)
40th Anniversary Apollo II (£9.15 at Amazon)
2 different Flower Fairy Ones
Few others including a really cool round 500 piece Mr Ben Jigsaw (which is £11.50 at Amazon)