There's plenty of small-sellers with copies of XP on eBay. Having that on something like an XP-era Panasonic Toughbook, plus an up-to-date Linux ** , makes it a very useful "go-to" machine for things like expanding BIOS update files and putting them onto a USB "thumb", and reconfiguring difficult-to-access routers etc.
But don't ever let XP get anywhere near the Internet, it's likely to self-destruct.
** With the caveat that sometimes laptops come with "unusual" video hardware, which might be supported for a few years by Linux and then effectively dropped. I've got a Sony for the sort of jobs I mentioned where I've had to stop with a Debian which is now several versions out of date, which has a knock-on effect on the version of FPC and in particular Lazarus which will run.
MarkMLl