The 1929-S is the last of the early, i.e. 1916 to 1929, Walking Liberty half dollars. Like all the early date Walkers this issue wasn't saved in any meaningful quantity at the time of issue. Mint state survivors are scarce and Gems are very scarce. The typical 1929-S has somewhat subdued luster. Strike is not the problem you see in the later S-Mints but sharply struck specimens are the exception as most have a little softness in the central devices.
According to a notice in the June 1934 issue of The Numismatist (p. 416), collectors could still purchase Uncirculated 1929-S Half Dollars directly from the U.S. Treasury for "the face value of the coins and an amount sufficient to cover the mail charrges by first-class mail."