A very large chunk of the comics out there get published in what are called Trade Paperbacks. The majority of them are soft cover, but there are some hard cover ones as well. Trades usually have anywhere from 4-8 issues in a single book, giving you more bang for your buck. The fact that you can put them on your bookshelf adds additional value in my opinion.

Comics are, for the most part, a pulp medium. They're stories boiled down to the most important elements, the action, the drama, the suspense, what have you. As a result they're often a very fast and a very easy read. What makes comics amazing though, is how the artwork and the words on the page work together to tell the story. Before you even start reading comics, I recommend you check out Understanding Comics by Scott McCloud. It is to comics what film school is to movies. After reading it, you'll have a whole new appreciation for the medium and you'll be able to pick up on things you never picked up on before.

I know you're hesitant about spending money on comics. To be honest? I wouldn't recommend you buy very much without experimenting first, seeing what you do and don't like about the medium. Fortunately, libraries carry graphic novels/trade paperbacks and you can get your hands on A LOT without spending a dime.