In reply to dek:
In short, no. Velvia 50 is now unavailable and Velvia 100 is pushing £4 a sheet!
The Fuji shop and discountfilmsdirect.co.uk occasionally have deals on short-dated stock, but ebay is your best bet. A few months back a mate and I clubbed together, spent a while scouring ebay, and bought ~700 sheets for ~£2 or less a sheet. By the time my freezer stocks run out I suspect processing may have the same issues.