I really enjoy using Montsavon soap having picked some up in a French supermarket this summer.
It works best for me in a face lathering style.
I had planned to stock up on it and offer it to folk on here but I can see that the site quoted by alex98uk (French Click) has beaten me to it on that score. Would anyone be interested if the price was better than the £2-39 +p+p quoted by Frenchclick?
The original question was how long does it last?
In my experience one 'bol' is good for about 40 shaves (its quite soft soap)