My recent experience with upgrading the original 1GB memory to 2GB in my Acer Aspire One 522 involved figuring out how to open the case to get access to the internal components. Once the case was open, the disk drive was right there in front of my face... and that got me thinking about something I had been intending to try for quite some time - swapping a disk drive for a Solid State Disk (SSD). I checked around a bit, and found a Samsung 830 Series 128GB SSD for about 175 CHF (about £115). Samsung actually offers this SSD in at least three different packages - a "bare bones" of just the drive itself, a "laptop upgrade kit" which includes a 2.5" drive spacer bracket, a USB/SATA adapter cable and a copy of Norton Ghost, and "desktop upgrade kit" which includes a 3.5" mounting bracket, and SATA and power cables.
For my purposes, I could easily have used just the "bare bones" package, because the disk mounting bracket in the AO522 was a perfect fit for the Samsung SSD, and the drive thickness was not significant, so I didn't need the spacer; I wasn't about to use Norton Ghost to copy the original disk drive to the new SSD (or any other Norton product for any other purpose, to be honest...), when I could use Parted Magic, System Rescue CD, Clonezilla or various others to accomplish the same thing. In this case, however, I decided to simply reload the installed operating systems from scratch on the new SSD. I don't have the time, interest or patience to load Windows from scratch again, and fight for a day and a half with Windows Update again, so I ditched Windows and made this a Linux-only system.
I did some very simple timing of several different Linux distributions on this system before I changed the disk drive, and found that they all took about one minute from the GRUB menu to a ready.-to-use desktop. I repeated those tests with the SSD, and found that the average boot time had been cut to 30 seconds or less! The overall impression of using the system is faster with the SSD as well.
This is neither a "very low cost" nor a "very easy" upgrade, but if you have a bit of money and a bit of time, the payoff is very substantial.