Think of Marvel Unlimited as the Netflix of comics. It lets readers access thousands of great Marvel comics from The Avengers to X-Men, all through a handy monthly ($9.99) or yearly ($69) subscription.
Titles are browsable by series, character, creator or comic event and are then either streamed to the iPad or downloaded to read offline. You can store up to 12 comics offline for reading later — ideal for classrooms that lack wi-fi or long school trips on the bus.
If you want a trial of the Marvel Unlimited experience, there are many free issues included in the app, so you can decide if it will be beneficial to your class or school. As the Marvel subscription is handled externally, you could potentially have one school account that all the iPads can login to.