Unless I’m mistaken, Infinite Jest was published simultaneously in hardcover and softcover - I have a paperback copy of the first edition with the “Vollman” misspelling, just like you’d find on the first edition dust jacket.
For me, reading a first edition signed by the author is like a dining experience. The ultimate reading experience would be to read the galleys with the author's proofs. It has to be the work of an author I like, of course.
I buy books (almost all the time), but what if the 1st edition, printed in the UK, where it was written, and the 1st American edition? Given that both were printed in 2024, what would be any difference in value? Why? Or how about the 1st German edition, meaning the first translation? (I usually think of those as less valuable.)