Today found a book I'd idly considered buying for a while. Found it at a used shop for $95. It's a first edition of a 2nd novel by a now-rather-successful novelist, and it's signed. This is the one that turned him from 'dabbler' into 'big gun'.
So I got book back to office, turned around and looked it up on alibris.com. It's selling out there for $15 more than I paid-- in a NON-first edition, UNsigned.