Article received by two boys free of charge (7)

I believe the answer is:

donated

I'm a little stuck... Click here to teach me more about this clue!

'free of charge' is the definition.
Both the definition and answer are adjectives. Maybe there's an association between them I don't understand?

'article received by two boys' is the wordplay.
'two boys' means two substitutions for 'boy'.
'article' becomes 'a' (the indefinite article in English).
'received by' is an insertion indicator.
'boy' becomes 'dont' (I am not sure about this - if you are sure you should believe this answer much more).
'boy' becomes 'Ed' (short for Edward).
'a' put inside 'dont' is 'donat'.
'donat'+'ed'='DONATED'

Can you help me to learn more?

(Other definitions for donated that I've seen before include "Presented" , "Given" , "Gave" .)

I've seen this clue in the Evening Standard.

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