Tomahawk cruise missile: $1.2 million, plus costs of fuel, crew, and deployment of warships to launch the missiles
Hellfire missile: $100,000, plus costs of fuel, crew, and warplanes to fire the missiles
Small Diameter Bomb: $30,000, plus costs of fuel, crew, and warplanes to drop the bombs
B-1 bomber: classified; estimated cost somewhere between $1.5 million and $2.4 million, plus $58,000 an hour to operate
F-15E Strike Eagle fighter bomber: $108 million, plus $39,000 an hour to operate
F-22 Raptor: $350 million, plus $68,000 an hour to operate
The United States uses much of this expensive firepower in Syria and Iraq against American-made materiel (artillery and tanks) that ISIS/ISIL seized from the Iraqi Army when it disintegrated in June 2014.
(Sources: Robin Wright, “The Vortex,” The New Yorker, December 8, 2014; Yahoo News; Defense Daily)