Prices on Ebay I found are relative. I sold a bunch of my old CDW classic Traveller books, & all my Paranoia Press stuff some time ago to pay off my new central air & furnace, some went for weird prices & some relatively cheap. During a brief period of flushness, I managed to replace most of the Paranoid Press stuff & get a few ship minis. Now with my eye problems, I've had to unload most of my Traveller stuff, some of it going at relatively low prices. I've had more success selling my Godzilla & Anime collection than the Traveller stuff.
But after a year & a half of treatment they've stopped my left from leaking fluid & though I no longer have stereo vision & looking forward to
being to put together & paint some of the remaining minis I have once my vision adjust to the new lenses.
On buying, I found if you're a diehard gamer & want minis for your game, & don't mind the condition you can get Traveller cheap. I picked up cheap some time ago a group of minis very cheaply. Though they were marked Traveller, some of the minis weren't, they were a little bent, one was broken (but repairable) & they were packaged in just plastic baggies. They were what I wanted & cheap. Fortunately, I got them just before my vision problems & they cleaned up nicely.
Kinda like how I got my copy of Azhanti High Lightning. I had gotten a copy of the rulebook by itself in a bundle of books. Later on Ebay I looked around a found a Azhanti boxset rough box, no rulebook, & good price. Admittedly I was luckly, but it was better than paying the $75.00 plus for a complete game.
Plus thanks to a wise investment partially funded by my loving wife I have Profantasy. I can replace some of the Judges Guild, etc., floor plans I sold or lost (My FASA Staport Module Hotel plans was missing from my portfolio after my last con) with new plans. Plus it's good training for my remaining eye.