Just noticed today that the Kindle Store now has some Marvel Comic story collections available, in addition to their DC offerings.
Including classic stories like:
X-Men: Days of Future Past
Wolverine (mini series)
X-Men: Dark Phoenix Saga
Even Secret Wars
If you've subscribed to Marvel Unlimited, this isn't really necessary but if you haven't, or if you don't want to wait for more recent releases that haven't shown up yet, something to keep in mind.