[The IL-22 escorting the A-50 was also shot down.]
So there are several versions of the A-50 and the most recent upgrades are said to make the plane worth $500 million.
But I'm pretty sure all these numbers are "equivalent" dollars, meaning what it would cost the US to build such a plane, not necessarily what Russians themselves spent on it.
Regardless, by any measure, they are expensive pieces of hardware.
Also, the A-50s mission is pretty easy to guess, since Russians seem to believe Ukrainian air defenses have collapsed and so Russians are eager to take advantage of opportunities to send their SU-34s and SU-35s to long-range bomb Ukrainian targets.
Turns out, Ukraine's air defenses are not quite as bad as reported, and another result has been at least six Russian jets shot down in recent days.
Finally, if I understand correctly, the kicker for this whole story is, that A-50 was nowhere near Ukrainian front lines, instead, it was well east of the Azov Sea and out of range of every anti-aircraft missile Ukraine has... except one, a stone-age era Old Soviet S-200 SAM -- the kind which used to shoot down American F-4s over North Vietnam.
Only the Old Soviet S-200 has the 200+ mile range to reach out and touch that A-50, and how many old S-200's are even operational these days?