There may well be money in backing it for £50 (4)
I believe the answer is:
till
'there may well' is the definition.
I can't judge whether this definition defines the answer.
'money in backing it for ps50' is the wordplay.
'money' becomes 'l' (L can mean 'pounds').
'in' is an insertion indicator.
'backing' says the letters should be written in reverse.
'for' says to put letters next to each other (I've seen this in other clues).
'ps50' becomes 'l' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'it' put after 'l' is 'lit'.
'lit' written backwards gives 'til'.
'l' inserted into 'til' is 'TILL'.
'be' is the link.
Can you help me to learn more?
(Other definitions for till that I've seen before include "Work on farm" , "Money box" , "Cashbox" , "Money receptacle" , "Prepare land for cultivation by ploughing etc" .)