Plan to put a pound in the kitty (4)
I believe the answer is:
plot
'plan' is the definition.
(I know that plot is a type of scheme)
'a pound in the kitty' is the wordplay.
'a pound' becomes 'L' (abbreviation e.g. Lsd - pounds, shillings, pence).
'in the' is an insertion indicator.
'kitty' becomes 'pot' (both can mean a shared fund).
'l' inserted into 'pot' is 'PLOT'.
'to put' is the link.
(Other definitions for plot that I've seen before include "lost in poor judgment" , "part of garden" , "Secret scheme or plan" , "... of story, family ..." , "Conspiracy, secret plan" .)