Be sparing with the first man in the list (6)
I believe the answer is:
scrimp
'be sparing' is the definition.
(as in scrimping and saving)
'first man in the list' is the wordplay.
'first man' becomes 'm' (sst letter of 'man').
'in the' means one lot of letters goes inside another.
'list' becomes 'scrip' (I can't justify this - if you can you should believe this answer much more).
'm' inserted within 'scrip' is 'SCRIMP'.
'with the' is the link.
Can you help me to learn more?
(Other definitions for scrimp that I've seen before include "Pinch and save" , "Subsist on a meagre allowance; be thrifty" , "Practice economy" , "Skimp, stint" , "Use or do less than is needed, be mean" .)