A revolutionary and a writer reduce the cost (7)
I believe the answer is:
cheapen
'reduce the cost' is the definition.
'cheapen' can be an answer for 'reduce' (I've seen this in another clue). I'm not certain of the 'the cost' bit.
'a revolutionary and a writer' is the wordplay.
'a revolutionary' becomes 'che' (Che Guevara the Marxist revolutionary).
'and' means one lot of letters go next to another.
'writer' becomes 'pen' (something which writes).
'che'+'a'+'pen'='CHEAPEN'
Can you help me to learn more?
(Other definitions for cheapen that I've seen before include "Decry or devalue" , "Cut" , "Demean - make less expensive" , "Reduce worth, degrade" , "discount" .)