Niecie - depends on how strictly legal you want to be, if you want XP... What I'm getting at is that there are copies on the 'net, but if your other half works in a number of professions, not just the police, he might be sniffy about hunting for it on a file sharing service as it would not be a strictly 'supported' copy, iyswim... a 'cheap' one might be the sort of thing you may find in the small ads of a local newspaper...
There have also been a few PC sellers on Ebay who supply a desktop PC with XP Pro installed, along with an XP CD (and when I've bought new machines in the past, running XP, none has come with an XP CD, which I considered a swindle, but learned from it).
As a software designer, I should be very hot on any copyright infringement, but I see it more from a consumer's viewpoint and my major criticism is that some things cost far too much - MS Windows 7 was listed the other day on a big IT website at 200 pounds plus. So, while I have legal copies of XP (came with new PCs) and don't use MS Office myself, I would only consider reporting someone using illegal copies if they were doing it for their own profits (selling copies at car boots, week in, week out) or on a major scale (price list of software, 100s of items).
In the current economic climate, MickeySoft could probably afford to give it away free for 6 to 12 months, to help (a) encourage people to use it, and (b) help businesses save on upgrade costs, without it really dreadfully denting the profits at MS.
They decided on a $50 version of XP for Thailand {just to stop there being hardly any sales as pirate copies were being sold in markets for a few dollars each}.
Also there's a problem with PCs having Windows - you cannot transfer the licence to someone else, legally, so even if you wanted to donate a bunch of PCs to some charity or childcare group (seeing that might be topical) they would be unable to legally use Windows - they're duty bound to either get a new licence with a CD from some shop, or scrub Windows.