I bought a second-hand RAM stick! (in this economy!?) Got an extra DDR4 8G 2666MHz for HKD250 (~USD32) for my server so it now has 16G. Had a mild panic when the server started beeping after inserting the RAM stick, but changing the slots from 2+4 to 1+3 fixed it. This was my first own second-hand purchase (the Wii U was basically bought through my dad) and the experience was quite pleasant. Note that I went to a physical cluster of second-hand shops instead of buying online. I think that has contributed massively in avoiding scams. May return to buy more other stuff in the future.