I'm not real familiar with Panelfly, but it appears to be an iPhone application that allows you to download comics within it (rather than each comic being a separate iPhone application). The application costs $1.99 to download, with single-issue comics costing 99 cents and graphic novels ranging in price from $3 to $10, (at least in terms of the titles listed on their iTunes page). Per the press release, NBM's graphic novels will cost between $6.95 and $9.95.
“It’s clear this is the future where readers increasingly have a choice as to how they want to read their comics,” said NBM publisher Terry Nantier, “and we consider ourselves purveyors of graphic novels, not pushers of print publications. Any way you want a quality, engrossing novel-length comic, we’ll make that available, whether print or electronic.”
NBM graphic novels that will be added to Panelfly's catalog include Brownsville, Flower and Fade, Unholy Kinship, Lindbergh Child and North Country. Panlefly also carries several SLG titles, like Rex Libris, Chumble Spuzz and Zombies Calling, as well as titles from Picturebox and Sterling Publishing.