diffraction grating suppliers

Hi,

Does anyone here know of a reasonably priced supplier of diffraction
gratings suitable for webcam spectroscopy?

I've found some suppliers of holographic diffraction gratings which are
very reasonably priced but are very dense, at ~700 lines/mm. It seems
that a practical size is around 100 lines/mm.

There are references online, including on the pages of posters here, of
a French company Jeulin supply such a cheap grating but their website is
in French (not that thats surprising but it means I cant understand it!).

Spectroscopy is something that I'm just starting to experiment with and
so dont want to spend too much on expensive gear. I'm currently trying
to get the 700 l/mm grating and a prism the right distance from the
webcam to get a spectrum (not the grating and the prism at the same time
of course - I've learnt that much!).

Cheers,
~Al