An easy way to find out what's on special offer in Sainsbury's is to check their website www.sainsburys.co.uk. Most of the special prices listed online are available in the shops. It also shows the date each offer ends, which is handy for planning future trips.
And just to let you know, it seems that if you want to know what is on special offer in Tesco up North , you can also just check www.sainsburys.co.uk. Last week visited both stores and found they had many exactly the same offers. Wonder what is going on there.