I will start...
I live in India. My main source here many years back was Diamond Comics
and then, for a short run, Egmont India
(now named Euro Books). But today it's very rare to run into Diamond Comics or Indrajals (you find Euro Books comics but they are repeated stories): by "rare" I mean once in 4-5 years (at least for me, as I don't actively scout for comics in the small second-hand book shops you'll need to visit and be lucky).
So today my main source is my own website
for the current online Phantom Dailies and Sundays, and also for archives that go back till 2004.
I had left reading the newspaper strips for a few years so I'm happy catching up with the archives at my own pace. That said, I wouldn't mind variety in Phantom stories and am looking forward to sourcing tips from others.