An old penny one pound includes freely (2-3)
I believe the answer is:
ad-lib
'freely' is the definition.
(short for ad libitum, 'at one's pleasure' in Latin)
'an old penny one pound' is the wordplay.
I cannot quite see how this works, but
'an' could be 'i' (Roman numeral for one) and 'i' is located in the answer.
'penny' could be 'd' (pre-decimalisation abbreviation for penny) and 'd' is located in the answer.
'one' could be 'a' (a thing is one thing) and 'a' is found in the answer.
'pound' could be 'lb' (abbreviation for the unit of weight) and 'lb' is located in the leftover letters.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).
'includes' is the link.
Can you help me to learn more?
(Other definitions for ad-lib that I've seen before include "Unprepared remark" , "Off-the-cuff remark" , "Extemporise" , "Depart from the text" , "Unscripted impromptu remark" .)