Amazon now sell the range of Bridgedale walking socks (probably the best there is). Some prices are not discounted or only discounted by about 10%. However, there are some good deals to be had. For example:
Bridgedale Socks Endurance Trekker, size large, colour gun metal £6.99 (from £11.99). Similar deals to be had for the women's range, and the comfort summit range.
You will need to add postage (which is extortionate at almost £6), but it is free postage if your order is over £15, which is easy to do with a couple of outers and some liners.