I think it's a good deal for HP everyday paper 500 sheets of A4 paper is now buy one get one free. So £4.99 gets you two packs of 500 sheet printing paper.
Cheaper than most non branded ones as sainsburys selling their own multi purpose ones for 3.99 for 500 sheets.
No idea if it is store specific. Can't upload photo as I'm on my phone.
Bought it at new cross sainsburys.