I just got my cubes through Counters Direct (
www.countersdirect.co.uk/products.asp?cat=700 -already mentioned on the first page of this thread, just under a different name-great company by the way), and it cost me just over £70 (including £15 shipping) for 21, 12"x16" stainless steel grids, and 40 connectors.
They're excellent quality (very sturdy too), although the holes in the grids are a little larger than recommended on here (just under 2" instead of the prefered 1.5").
What are the cubes from Argos like? It's a bit late for me if they're just as good as what I have, but it's handy to know for future reference.