The Works, say, stocks pretty light (10)
I believe the answer is:
everything
'the works' is the definition.
(I've seen this before)
'say stocks pretty light' is the wordplay.
'say' becomes 'eg' (both can mean 'for example').
'stocks' indicates putting letters inside (stocks can mean carries or contains).
'pretty' becomes 'very' (pretty can mean very or considerably).
'light' becomes 'thin' (similar in meaning).
'very'+'thin'='verythin'
'eg' placed around 'verythin' is 'EVERYTHING'.
(Other definitions for everything that I've seen before include "The whole shebang" , "All that is; life in general" , "The whole lot" , "All items" , "the works" .)