A few years ago, after reading everything in the Hainish Cycle, I decided I'd try and get the whole thing in print. I'm not a serious collector, not necessarily after first editions or otherwise rare editions; but I did want hard covers, and I wanted editions that had dust jackets with all that funky scifi art of the 60's/70's/80's. So far the Hainish books have been good to me in the sense that none of it has been really rare and it's mostly under the 100 usd/eur point as long as you're not looking for signed stuff.
Unfortunately it gets a little weird with The Word for World Is Forest: The only good looking hard cover happens to be on one of the earlier editions and while I doubt it's truly rare, it's rare enough people start asking a lot for it. I finally got lucky and some kind bookshop on ebay put it up for less than 100, dust jacket and all, and I finally get to add it to the shelf.
It's not my favorite of the Hainish Cycle, but it's an easy recommend (I recommend everything and anything from Le Guin). I know it's a favorite for a lot of folks. Anyways, if you're just getting into collecting print scifi, bookfinder.com is fantastic for what it is (aggregator for the inventories of the big used book operations), and I guess every once in a while ebay can work out.
Devil's advocate: if you do things the legit way, absorb the ads or go for the pay tiers, do you think there's ever a point the advertisers and platforms say "this is the right amount of ads." ? Seems like it's an infinite process of cramming in more garbage. Personally I'm happy to engage in the arms race because it's not bothersome to me personally, and I'm fine with some "theft" as long as I'm paying back into the creators by whatever their preferred support structure is.