Keep an eye on HotUKDeals website, quite often some good Dell deals. I think someone at work bought a base for 150 recently.
Any good ?
Intel® Pentium® Dual-Core E2180 Processor (2.00GHz,800MHz,1MB cache)
Genuine Windows Vista™ Home Premium with Service Pack 1, 32-bit - English
17in E178WFP WIDESCREEN UK/Irish Black (1440 x 900) TCO99
1024MB 667MHz Dual Channel DDR2 SDRAM [2x512]
250GB (7200rpm) Serial ATA Hard Drive with 8MB DataBurst™ cache
Integrated Intel® Graphic Media Accelerator X3100
48x CDRW/DVD Combo Drive
Dell™ Entry Quietkey USB Keyboard - UK/Irish (QWERTY)
Dell 2 Button USB Optical Mouse
Subtotal £179.00 Ex. VAT & Shipping
But look out for codes etc to get free shipping and possibly more off.
http://configure.euro.dell.com/dells...=D062023&s=bsd
Alternatively build your own from the classifieds on this site. If it's just web browsing and general office applications an old P4 or socket 939 AMD will do you fine, I've often seen motherboard/cpu bundles being sold as people upgrade.