Been off of IJ for a while, but here's my recs: certainly agree with Gaiman/Sandman, but in a more general sense I'd rec the Essential (Marvel) and Showcase (DC) books. These are large volume (black & white, sorry) for $20 or less, covering a large range of characters. Like horror, mystery, and/or suspense? Try Phantom Stranger, House of Mystery, and/or House of Secrets. The stuff showing up in the essential/showcase formats tends to be a bit older (the Booster Gold Showcase tends to be one of the more recent ones, and that's the first series from the 1980s). I'm also gonna rec the Savage Sword of Conan trades that Dark Horse has been producing (also b/w, $20) 'cause they're neat.