There are a lot of tools available to the out-of-print book shopper. The one I use most often to search for trades is cheapestbookprice.com, mostly because it is so easy to interface with. And I can usually trust the results - if something appears as a hit on that site, the odds are good I'll be able to actually purchase the item at the listed price.
There are plenty of other options like bookfinder.com available. Boofinder searches through far more sites, but the results are a bit dodgy. You're going to get results that aren't reliable. When you type in the title or ISBN of your latest TPB discovery, it will send you to sites where the book was once sold but isn't currently available.
It's going to show you sites from Timbuktu and tell you that they have a copy of Gambit: Hath No Fury for 7 gazelle pelts. I don't do business like that.
One sort of in-between site that I use sometimes is http://www.dealoz.com/, because it searches quite a few databases including current eBay auctions. This is something that neither bookfinder nor cheapestbookprice offers.
It isn't as helpful as it could be, because booksellers on eBay are not usually savvy enough to add the ISBN number of their trade paperback on their listing. But you will find some bargains that way.
I think especially for the beginning TPB hunter, running your list through Deal Oz is a sound investment of your time. You're going to get results from all the old stand bys like Half and Amazon, plus some weird results, plus those current running auctions. It's an easy tool to master and great way to introduce yourself to the book trade.
Hidden Gem: Captain Marvel (Vol. 5) Marvel, 2002 - 2004
Peter David did what any writer would do with this character: give him god-like powers, cosmic awareness, and have him become so overwhelmed with these abilities that he goes stark raving nutters. Oh wait, that's right. Only Peter David would do that.
What a truly odd and wonderful journey this run turned out to be. Fans bristled at Genis's madness and ignored the book in droves, causing it's far too early demise with issue # 25. What a pity.
This series had ginormous brass balls, and it was unique. David was most interested in tackling the idea of predestination and determinism, but also delved fairly deeply into morality and religion as well. Not your typical funny book, to be sure.
Each issue had an increasingly more bent and more powerful Captain Marvel challenge every one of the readers assumptions about their relationship with God, the universe, and their ethics.
Occasionally preachy? Perhaps a bit, but nearly impossible to avoid given the subject matter. There is no agenda being crammed down the reader's throats, here, because Rick Jones acts as a buffer.
When the subject matter gets too heady and Captain Marvel threatens to spiral into an obtuse digression into metaphysics, earthy Rick is there to ground things and express the kind of disgust and bewilderment that the book's readers are apt to. I've never read anything quite like it.
If you like your comics to challenge your brain, I highly recommend picking up the run, currently available in 4 TPBs:
Captain Marvel Vol 1: Nothing to Lose
Captain Marvel Vol 2: Coven
Captain Marvel Vol 3: Crazy Like a Fox
Captain Marvel Vol 4: Odyssey
Right now Vol 1 is difficutl to find for under $30, and Vol 3 is starting to head that direction as well. It's quite possible that these are lying about your local comic shop at cover price, though. And if not, a little patience and diligence will usually produce a bargain. Happy hunting!