Open Office is free for any use. Microsoft Office is ~£40 for home educational use eghttp://www.hotukdeals.com/deals/microsoft-office-2010-professional-/710183
However, for business use, Microsoft Office Home and Business 2010 costs ~£153 at Amazon or Ebuyer, for just the license key or ~£178 if you want the DVD. To get a license for the same version of Office with a new Dell is ~ £163.
I have enough disks already, but I need an extra license for a new computer. You could also use the license key if you buy a computer which comes with a trial copy of Office.
If you log onto http://www.quidco.com
and then log on at Comet, you get a 10% discount voucher for office software, as well as 3% cashback (which will bring it down to £130.94).
Delivery is free, to get it by Monday 15th. You can get it sooner than that if you pay for delivery. You can also collect it from a Comet shop tomorrow,and that is free too.