Morrisons have 20% off some Gaviscon products, it makes a 600ml bottle just over a fiver. I buy this a fair bit and it's rarely on offer, so this is an excellent price. There was signage so probably nationwide, they had sachets and tablets in the offer and a 300ml bottle, all 20% off. Cannot comment if they're good deals as I don't remember prices or normally buy them.
It's usually about £7 or £8 quid in supermarkets