We launched 59 Tomahawk missiles onto a Syrian airbase last night. Those missiles cost $750000 apiece last time I looked. So that's $44 million, just for ordinance. It appears to have taken effect. Fox News approves, the Russians haven't declared war, and we didn't loose any pilots. All good things.
We could have done an airstrike with 1000 pound smart bombs. Plain iron bomb costs about $1000, the smart bomb guidance kit probably doubles that. Jet fighter bombers cost about $10000 an hour to operate. Call it a four hour mission, and dispatch 30 aircraft, two smart bombs per plane. Comes to $1,260,000 for the mission. It does risk loosing pilots, which has a terrible political fallout.
Time will tell how things turn out in Syria.