According to Coin Trackers, there were 138,000 1915 half dollars produced without a mint mark, and 1.6 million 1915-S half dollars. As of August 2014, the rarer half dollar without a mint mark has an estimated value of $157, even in poor condition.
The more-common 1915-S coin has an estimated value of $17 in poor condition, which is still significantly above the $7 that the silver in the coin is worth. As with all collectible coins, the condition of the coin makes a huge difference in its value. The 1915-S in perfect condition has an estimated value of $1,700, while a perfect-condition 1915 without a mint mark can be worth as much as $4,500. The year 1915 was the last in which the Barber half dollar was minted.