I needed to upgrade the memory in an old computer I gave to some art students who had started up a small business and were limited financially.
The computer has an old Athlon XP processor and only 256 megs of RAM. I was concerned as older RAM was a bit pricey, but this was at a decent price.
It just snapped in (taking anti-static measures of course such as a wrist band with the computer turned off and the on switch pressed first to remove any residual power) and I put Xubuntu (a version of linux) onto the PC and it brought the old thing back to life.
Money well spent bringing an old PC back from the dead which works well enough for the art students to check email, manage the website where they sell their goods and even watch a bit of youtube.