I appreciate the links. I found the free comics on Marvel Comic Store when Avengers vs. X-Men #0 was advertised on Marvel's Facebook a couple weeks back, and downloaded a few issues since then. Glad that I know the schedule now, so I know when to take my weekly trip to the site.
There's also the Marvel DCU. Free Digital Comics | Comics | Marvel.com This was updated with weekdaily free comics, but recently it's been relegated to free comics every Friday. Looking back through the 262 constant comics, it's mostly all-ages stuff, but there iss some cool stuff, like the entire runs of X-Men: First Class, Wolverine: First Class, Mary Jane, and Spider-Man and the Secret Wars. As for individual issues, Fantastic Four #587, The Avengers #9, #12 and #270, Uncanny X-Men #373 and #389, The Invincible Iron Man #58 and #500, Deadpool Team-Up #887 and I Am an Avenger #1.
It seems Marvel NOW! isn't enough of a starting point - decades old relaunches are good enough.
Although, for those who haven't read the Lee issues, a number of Lee #1's are on the free section. Interestingly, Avengers #1 redirects to the not-free Avengers #1 1/2 which I'm still interested in reading. Bah.