First of all, do you live in a town with a public library? If so, investigate their catalog for what Batman-related or Green Lantern-related books they have in stock. You might not get the best results, but at least it will be inexpensive. You might have to go to interlibrary loan if you live in a small town or not in North America.
Okay, just googled Lancashire libraries and ... 274 results for batman. And the first three pages worth don't have anything at my local (ormskirk for those who care). Many interesting titles however, thanks.
Huh, they also have a DVD of scooby doo meets batman. I am quite literally speechless at that.
Edit- my local has 33 titles, all of which look dull. You'd think in a university town there would be more stuff like that.
edited 17th Oct '11 9:27:24 AM by TheoneandonlyJoseph
Yeah, Great Britain isn't the best place for getting inexpensive editions of American comic book graphic novels.
Tell you what. If you'd like to see just fragments of various Batman stories, here's a link to the Scans Daily posts featuring his tag. http://scans-daily.dreamwidth.org/tag/char:+batman/bruce+wayne
If you're not familiar with Scans Daily, avoid the comments sections on any comic that was new when the scans were done—that's where most of the wankery is. "Great or weird stories of the past" tend to have much more calm and reasoned responses.
And after you're done with Batman, you can look for the Green Lantern tags.

I wish to read key dc universe story lines from before the reboot, particularly from the bat family (and I mean the entire family, not just bats himself) and green lantern. What story lines do you recommend, and how do I get them (preferably cheap, since I am a cheap b****** on a budget)?
Note- I have already read killing joke, but thats it.