Having a food allergy (Gluten) I have to trawl all of them to get a range of goods as some are only available in one. 
In terms of those wider stocked or not gluten affected anyway I use the Trolley app to see where the best prices are. Typically most products are on offer somewhere e,g, currently a 4 pack of Activia yoghurts is cheapest in Asda @ £1.75. Then their are the the various mobile app offers which mean every fortnight currently a bottle of milk (two pints) is 75p at Waitrose and around 20-27p more at Sainbsburys for as many as I want. At Asda last night I got a £1 off 2 £1.75 packs of yoghurts.
	
		
			
		
		
	
			
			In terms of those wider stocked or not gluten affected anyway I use the Trolley app to see where the best prices are. Typically most products are on offer somewhere e,g, currently a 4 pack of Activia yoghurts is cheapest in Asda @ £1.75. Then their are the the various mobile app offers which mean every fortnight currently a bottle of milk (two pints) is 75p at Waitrose and around 20-27p more at Sainbsburys for as many as I want. At Asda last night I got a £1 off 2 £1.75 packs of yoghurts.
				
  she's looked at the promo label haha

