One gets nothing for it (3)
I believe the answer is:
ten
'one' is the definition.
The answer and definition can be both quantities as well as being singular nouns.
Maybe you can see an association between them that I can't see?
'nothing for it' is the wordplay.
'nothing' becomes 'en' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'for' is a charade indicator (letters next to each other) (I've seen this in other clues).
'it' becomes ''t' (abbreviation. e.g. in 'tis).
'en' after 't' is 'TEN'.
'gets' acts as a link.
Can you help me to learn more?
(Other definitions for ten that I've seen before include "X-WORD" , "Half a score" , "honour" , "Base of decimal system" , "Very young" .)