I don't think you can generalise that ALL the products in £1 shops are not value for money.
Yes, some items, if bought in larger volumes from supermarkes and chemists maybe better value, but that is not necessarily the point of buying from £1 shops.
It may be the case that the consumer only wants a specific size of an item that suits their budget and not a larger volume.
Also, the vast majority of items sourced and sold in most of the £1 shops are generally good value (not top quality) and suits the purpose that the consumer requires.
I think the draw of £1 pound shops is that when you are inside, you see other items that tempt you to spend more than what you had originally intended.
Given the growth of these types of shops nationally and internationally (99cents, 1 Euro) they must be providing consumers with a service they require.
We source many items for these retailers and some are exceptionally good value for money, given the alternatives avilable in the high street.
The success (and profit) is in purchasing the correct products at the right prices.