1. LibraryYou may not know this, but your public library is a great place to read comic books. Libraries all over carry graphic novels, manga, and comic book related material. They are often in the science fiction and fantasy fiction section and in the comic non-fiction section. Another cool thing is that you can even request certain comics and they will often buy them for you. The great thing is that they are absolutely free.
3. Forums/ClassifiedsForums of comic book fan sites, such as the one at About.com have places that people that are always looking to get rid of their comic books. There are also forum sites such as Craigslist provide places for people to post free classifieds. Be careful about dealing long distance as you may get scammed.
4. Comic Book StoreYour local comic book store is a great place to find cheap comics. They will often have sales to clear out back issues, and these can be a great way to score that comic you have been eying for some time. They may also have a cheap comics bin, for those, less desirable, comics. Comic book stores also will sometimes offer discounts if you open a, box, with them. This is where you commit to buying a certain amount of comics and when they come in to the store, they set aside what you want.
5. ConventionsA convention is a great place to find cheap comics. There are many vendors there and with the competition high, the pricing will reflect this. Take a walk around and see who is offering the greatest deal. If a retailer doesnt have a certain comic, but another one does, ask if they will meet or beat the competitors price. Another trick is to wait until the end of the convention. Many dealers wont want to drag their items home and may offer steeper discounts.
6. EbayEbay can be a great place to find cheap comic books. Due to the nature of the auction format, many sellers put their comics up at a low starting amount to avoid high insertion fees. This gives the buyer a great chance at scoring a comic book, series, or even collection. Be careful, the temptation to overbid and win the prize may be great, but it wont get you that comic for cheap. Let it go and check later for the same comic as you will often find multiple listings of the same comic.
7. Flea Market/Garage SalesThe classic place to find used items is the flea market and/or garage sale. Garage sales are seasonal and will mostly be found on the weekends. Many flea markets are inside and can be found year round. The great place about flea markets and garage sale is the chance to get a bargain. Always offer a lower amount than what is advertised. Do your research on what you buy though and it might be a good idea to bring along a price guide as well. Your local paper will have more information.
8. Internet Retailers/Sites
There are many great internet sites that have back issues and current comic books at great discounts. Comic book sites such as Mile High Comics offer steep discounts on current comics and back issues. If you check around and keep an eye on the site, you can get the best discount when items go on sale. Other sites, like WOWIO offer free downloads of comics.