How does one get into comic books?

This is a relatively simple suggestion. Google "best comic book stories of all time" or "best graphic novels of all time". Skim a few of the articles that come up. That will give you an idea of what's considered great by people who read a LOT of comics. Pick a few single issues first or maybe a multi issue storyline that's short (like 4 issues)  and BOOM you're on your way. Graphic novels are generally longer series like the awesome Watchmen collected into one big volume or often multiple volumes.

Next. How do you read these comics without investing any money?  Great question.  Depending on where you live, your local libraries can be a great place to read comics for free just like any other book. Library cards are easy to get and free if you don't have one already. My state has an online library system that allows users to search most of the libraries in the entire state and using your library card have any book including countless graphic novels  or dvds or cds sent to my closest branch (5 miles from my house) where I pick it up as well as return it.  I usually get it within a week sometimes longer but more often sooner.   Check to see if your library has something similar.

If you want to be even lazier and who doesn't?  I was turned on to this awesome site on an IMDb message board.  (Screw you jeff Bezos)  It's self explanatory.  comic books 

Hope this helps.