That figure only applies to the home-made, short-range Qassams. The larger and longer range Katyusha and Grad rockets cost thousands of dollars, and the Iranian-made Fajr-5 are more costly yet. Even the small rockets can result in property damage, injury and death. Let's consider an alternative "passive" defense - reinforcing buildings and constructing secure rooms. The cost for such work runs into the hundreds of millions of dollars. Would you say such is uncalled for because some projectiles only cost a few hundred dollars?
from the article: The porous shield of Israel's Iron Dome