I don't have a source for the drones or missiles used in this recent attack, but Forbes has an article from February titled, "$375,000 - The Sticker Price For An Iranian Shahed Drone". "Its delta-winged Shahed-131/136 variants are believed to have a range of approximately 500 to 900 miles." and "The documents show that a single Shahed costs $375,000 to produce." I'm not sure that's long enough of a range to make it to the Israeli targets though, so take it with a grain of salt.

The New Arab's article today about cost reports, "It is not known how much Iran spent on its attacks, though ballistic missiles in the country can cost up to $99,937 (₤80,000), The Guardian said."

Politico has an article from December called "A $2M missile vs. a $2,000 drone: Pentagon worried over cost of Houthi attacks". "The cost of using expensive naval missiles — which can run up to $2.1 million a shot — to destroy unsophisticated Houthi drones — estimated at a few thousand dollars each — is a growing concern, according to three other DOD officials." and “The cost offset is not on our side,” said one DOD official." I'm guessing those are the bottom end drones and likely not capable of crossing the distance between Iran and Israel. It does give an idea of how much it might cost for Iranian-backed groups closer to Israel to use drones in the future though.

It's hard to estimate the cost, as it is internal to Iran and a government effort. But in general, air defense tends to be more expensive than whatever it is shooting down. In this case, I am certain it is orders of magnitude difference. Iran's economy is in shambles, so they focus on cheap weaponry.