The value of material used by the poet? (10)
I believe the answer is:
wordsworth
'the poet?' is the definition.
(William Wordsworth, 1770-1850)
'the value of material used by' is the wordplay.
'the value' becomes 'worth' (I've seen this in another clue).
'of material' becomes 'words' (I can't justify this - if you can you should believe this answer much more).
'used by' is a charade indicator (letters next to each other).
'worth' put after 'words' is 'WORDSWORTH'.
Can you help me to learn more?
(Other definitions for wordsworth that I've seen before include "Poet (of the 20s)" , "Romantic poet" , "writer" .)