I do include most toiletries and other non-edible items in my supermarket bill though, e.g. printer paper and DIY odds and ends.
However, when I was in England recently when my mum was ill I was amazed at how CHEAP some things are in England compared to France. As I make my own bread I could not get over the price of flour in England - 40p for 1.5 kilos of self-raising or bread flour!!!!!! We pay the equivalent of £1.10 for 1 kilo!!! And all the two for one prices - cheese was soooooo cheap, sausages about 1/4 the price of French ones (not that I'd touch those gallic horrors with a barge pole). As for the price of things like Tescos shampoo, Vit C, lip salve etc. Grrrrrrrr!
So you can see it is hard here to be frugal. And I can't afford to go to England in the car.
