Sainsbury (& other supermarkets) sell a low cost brand of their own thin bleach in a large white moulded plastic bottle with a handle - 2 litres for 27p. Value indeed, especially when compared with the price of national brands of scented surfactanted versions.
Sainsbury also sell an own brand version of Original Thin Bleach in a pale blue plastic bottle, no handle, only 1 litre, price 67p.
I am at a loss to explain the difference in price. The label of the cheapest version informs me that the contents include water (>30%), sodium hypochlorite & stabilisers (<5% each). The more expensive version is more cagey – revealing only <5% disinfectants.
Just one of life’s little mysteries.