I bought a working PEB (with full sized 5¼" FDD) off of ebay for ~$50, not including shipping. It didn't come with any cards but I thought it was a pretty good deal considering that most sell for over 3x as much with as little as a disk controller card. Not to mention I could pretty easily make a card that combines the Flex Cable Interface, a floppy disk controller, and a whole slew of other things (coprocessor?) for less than the unit itself.
What do you guys think?