It’s a ton if you avoid things Poettering was involved in (anyone remember when Pulseaudio came out and its memory use when idle was insanely high? AFAIK that never got better, we just all got more memory; Systemd’s similar), don’t run a “modern” DE, and don’t use webapps.

That’s a lot of “ifs”, but that really should be quite a bit of memory.

In fact you can’t even really run Firefox or Chrome with a single light page on that, now. In one of the minimalist WebKit browsers, yes, but probably only 2-3 tabs and no webapps.