It is tempting to get a second one. Maybe a lower spec one (base RAM and HDD configuration) just to use for writing without the distractions of having a GUI. I do miss my tty-only 10-inch Intel Atom netbook sometimes. It was perfect for keeping lecture notes.
300 EUR is a good price (even more if you can install your own libreboot). The thing is, that over the last couple of years prices (on the market in general) have remained insanely high. RAM for example. I would personally consider buying a new PC only if you really need it, or if you don't plan to upgrade it soon.