If you've never read anything by the great Robert Sheckley and wonder if he's worth a try, then hearing about some comparables might be helpful -- even when, strictly speaking, there is no one comparable.
Washington Post book critic Michael Dirda, in his review of STORE OF THE WORLDS, listed these: Kurt Vonnegut's books, the sardonic comeuppance stories of John Collier and Roald Dahl, Edward Gorey's little albums, and reruns of "The Twilight Zone." Other respected practitioners of science fiction have compared Sheckley (when he's at his best) to Voltaire. The opinionated writer Harlan Ellison has said, "If the Marx Brothers had been literary rather than thespic fantasists ... they would have been Robert Sheckley."
I'd add this advice: If you enjoy anthropology as a mind-stretching experience (those strange other tribes are not us and yet are us), and if your brand of humor includes satire rooted in the age-old lesson, Lord what fools these mortals be, then this guy Sheckley's for you.
So a first foray into Sheckley's world should begin where? I think STORE OF THE WORLDS is an ideal port of entry.
Don't be misled by the fact this volume appears under the imprint of New York Review Books, whose reputation is built on the resurrecting of out-of-print literary gems. Sheckley may not a "literary" writer at least not as that term is generally understood. Not to worry. Your reward as a reader is not the quality of his prose (although he is no slouch in that regard). No, your reward is spending time inside a playful, fertile mind -- a mind that births ideas like some boundless cornucopia, ideas sometimes antic, typically sardonic, always honest.
There's one other collection of the author's stories currently in print to consider as an alternative: The Masque Of Manana. It's a hardback containing 41 stories, 15 more than the paperback STORE OF THE WORLDS. One notable story, "The Lifeboat Mutiny," which reviewer John Gault praises in his Amazon review on this page and which he regrets is missing from STORE, does appear in MASQUE OF MANANA. On the other hand, another fan-favorite "Watchbird," a cautionary tale that presaged by half a century the controversy over domestic use of drones, is found in STORE but not in MASQUE.
Still on the fence? You can get a complimentary taste of Sheckley in Amazon's Kindle Store which lists a dozen or more stories available for free download. Amazon seems to rotate stories in and out of the "free" category. Try these (available as of January, 2013): Watchbird; Warrior Race; and Cost of Living. Also worthwhile is Sheckley's short novel, The Status Civilization (it's also a free Kindle download, at least as of 01/2013).