My friend and I have been using this UK site for a bit now and found them to be the cheapest on the block.
If you are into DIY or woodwork and need screws and fixings, just look at the prices on here, I don't think you will find cheaper (from about 19p + vat for 100).
Postage is rather good as well, we ordered about 2,500 screws for his decking and other bits and with postage came to less than £20. The drill bits are great value, if bought in tens they work out at about the same price as you would pay for a couple in B&Q. They do have a min order value of £10 excl. vat & del.

http://www.leofixings.com/index.asp

John