250-300$ build cost if you buy components in bulk. Not counting the payload itself.

Basic FPV drones are rapidly getting countered/obsolete. The moment people start doing something smarter/custom the drones stop being cheap.

It's an unavoidable dilemma: commodity stuff is cheap, but easily countered; stuff that isn't easy to counter isn't commodity and isn't cheap. You probably heard "yes but you can JUST add a jamming-resistant radio, and a thermal camera, and autonomous recognition/coordination, and larger payload, and…", but that's just motte-and-bailey.

Plus the drones still need the payload. If they are used against armour, they need shaped charges, which aren't free. In practice they often get random RPG-7 HEAT warheads from Soviet stockpiles, but we can't compare that with newly manufactured western 155mm HE.

Adding context, before the war, according to internet sources, prices ranged from $3000-5000USD. Recently, they've been going for as much as $8600USD each.

A Howitzer itself ranges from $2m - 3.7m USD each.