I used to go to Forbidden Planet in Manhattan every Wednesday to browse new comics. But since my recent discovery of Comics by comiXology, the company that Amazon just bought for an undisclosed amount, I can't see myself regularly going to a comic store ever again.
ComiXology offers a well-designed app for buying and reading comic books from more than 75 publishers. It makes it easy to see new comics, which sell for the same price as in store, and it's easy to buy back issues, too. There are also always comics on sale, including collections for a great price.
Although publishers like Marvel offer their own buying and reading apps, comiXology's may be the smoothest and it is the most comprehensive.
Reading comics on a mobile device is a surprisingly good experience. On an iPad you can view the whole page at only slightly smaller size than you would in print. You can also view comics frame-by-frame, which is the only way to do it on an iPhone, and this is a fine experience too.
Digital comic collections won't increase in value like print comics in rare instances can, but they are much easier to store.
Digital comics are also much easier to buy. Only last night I went on by far my biggest and most expensive comic book binge ever, not to mention my first-ever in-app purchase binge, buying issues 103 through 120 of "The Walking Dead." It cost $40. That series is so good and it is so easy to buy comic after comic that I couldn't help myself.
It helps if you share an account with a friend who bought the first 102 comics and who will also enjoy anything you buy (probably in violation of the terms of agreement).
Comics, in case you haven't picked one up recently, are better these days than ever, with many sophisticated stories aimed at adults and creative series even appearing at Marvel and DC, in addition to sometimes less creative mega-crossovers and movie tie-ins.