A call to New York Times? It will be expensive (4)
I believe the answer is:
onyx
'it will be expensive' is the definition.
The definition suggests a singular noun which matches the answer.
'a call to new york times?' is the wordplay.
'a call to' becomes 'o' (I can't justify this - if you can you should give a lot more credence to this answer).
'new york' becomes 'ny'.
'times?' becomes 'x' (multiplication sign).
'o'+'ny'+'x'='ONYX'
Can you help me to learn more?
(Other definitions for onyx that I've seen before include "Form of agate" , "Black and white striped gemstone" , "material for making cameos" , "Stone-like marble with coloured layers" , "Chalcedony agate" .)