explosive is something like 20$/kg, rocket propellant (if used) would be somewhere in the same ballpark. it's cruise missile so another big cost will be small jet engine, electronics are a bulk of the cost, yeah. electronics are also what is responsible for bunch of new capabilities. new seekers? TERCOM (not on sea but yknow), maybe datalink? camera to feed image back to operator? good inertial guidance can get pricey. harden it all against jamming and EMP, keep all pieces non-chinese and assembled in usa, keep paper trail and things get expensive. and it all needs software too, and software has to be kept classified, so all devs have to have clearance

for 155mm artillery shell something like third of the cost is fuze, with second most expensive component being casing (30kg-ish piece of steel rather precisely machined on lathe and heat treated in specific way)