Then build it yourself. Personal Computer World magazine July 2008 on sale from May 15th. has the details. The spec. is as follows
Intel D201GLY2 motherboard with Celeron 220 1.2Ghz CPU soldered in place, onboard audio and video.
512 Mb memory
80 Gb. Sata hard disk
Case & PSU
Ubuntu operating system
Not included, monitor, keyboard, mouse.
Of course, since you are buying the components and building it yourself, the specification is very flexible. The above spec can be put together for under £100, however the article suggests an upgraded option with a smarter case, 1Gb memory and dvd writer bringing the cost up to £127.
Performance figures for the £99 version were better than those for an Asus eeePC.
It's a while since I looked at the cost of building a pc and it came as a surprise to me that you can put together a system for so little money.