Personally, I've been after the first edition ever of "Barbarella" for about 5 years. What can I say about this book? What's the big mistery about it?
Barbarella , by Jean-Claude Forest, firstly appeared in the french comic mag "Magazine V" in 1962, a complete shock for the public. Two years later, 1964, we see the space heroine in her first hardcover book. A striking pop-art cover, the publisher "Le Terrain Vague" (with a little help from Eric Losfeld) makes a hit out of its book. An US edition will follow in 1966, till the very last "first edition" in Europe, the italian one, 1975 (!!!).
The first edition disappears quickly through the years, and it's still - to these days - unavailable to most collectors, even on the web.
By asking around (other collectors, friends, shops) and surfin' the web a bit, I could get some prices for you, just in case you'll be lucky enough to get hold of one copy of the book.
A good french first edition (I'm talkin' about 1964, remember!) can be found for a $120-$250 price range, and this could be one of the highest prices for a given edition of "Barbarella". Following years' editions should be found for a much lower price (this price range applies to a ooo/ooooo grade, of course. You wouldn't pay that for a worn out book, would you?)