It tells you what the fare is (4)
I believe the answer is:
menu
'it tells you what the fare is' is the definition.
The definition suggests a singular noun which matches the answer.
'it tells you' is the wordplay.
'it' becomes 'men' (I can't explain this - if you can you should give a lot more credence to this answer).
'tells' shows a homophone (sound like) (I've seen 'told' mean this).
'you' is a homophone of 'u'.
'men'+'u'='MENU'
Can you help me to learn more?
(Other definitions for menu that I've seen before include "List of dishes available in restaurant" , "List of fare" , "List of items available in restaurant (4)" , "Range of dishes available" , "Food programme of restaurant" .)