The Bahlsen Pick Up! Biscuit 5 Pack which are usually £1.69 are currently £1 in Tesco. I also noticed that currently packs going on the shelves (might not be on all shelves just yet) have a 50p off next pack voucher promo inside running from 24.06.14 until 31.10.14. Whilst you can't get the two packets for £1.50 in one transaction, it makes them that in total after the second buy.
AND if you really love them, you can keep buying the discounted packs and essentially bring the price of each down to 50.0000000000001p if you buy enough of them!! A bargain after the initial outlay of a whole £1 on the first pack.
The Tesco offer is until 19th august