The Bab5 books are hard to find as some are out of print. I think I paid 30 dollars for one of the paperbacks. The trilogy I loved so much was the Techno-Mage trilogy. I also read the Psi-Corp trilogy which while written a bit more minimalist was fantastic. Shows you several generations of Psi-Corp, the origins and Bester's life story. Both of these trilogies blow Treklit out of the water IMHO.
I still have the Centauri trilogy to read, I'm getting to it, I'm working my way up to picking up Peter David again.