As May/Karen pointed out to the Hounds, this is an excellent price (less than what many individual books of the two-volume version regularly go for). With free shipping from Illinois, it's a nearly-impossible to beat deal. This version is the 1960 printing, and there's also a 1988 edition for about $6, also with free shipping, still a very good deal.
This link lists all the Doubleday copies they offer:
Many collectors will not be interested unless they're trying to complete their set of editions, but as gifts for someone who may be wanting to make their first foray into the Canon, a few bookmarks from a well-versed Sherlockian to a grandchild, niece or nephew, or children could be a really neat and thoughtful keepsake (especially with a heartfelt inscription).
Some of my favorite books aren't special editions or particularly rare, they're the ones that a grandparent took me to buy together, or it's a relative's favorite book with their ex libris bookplate in it—I only had one or two grandparents who were readers/book collectors, so I treasure those connections I have even more, now that those relatives are gone. (The attached photo is of Broca's Brain by Carl Sagan from 1979, purchased for $5.95 at Marshall Fields, apparently, by my grandmother who died 25 years ago; she loved Sagan's work and I remember watching Cosmos reruns on PBS with her.)