Donkeys carrying first of the goods (6)
I believe the answer is:
assets
'goods' is the definition.
(I've seen this before)
'donkeys carrying first of the' is the wordplay.
'donkeys' becomes 'asses' (an ass is a donkey).
'carrying' indicates putting letters inside.
'first of the' becomes 't' (1st letter of 'the').
'asses' placed around 't' is 'ASSETS'.
(Other definitions for assets that I've seen before include "Valuables, things worth having" , "One's goods and property" , "Resources or holdings ( 6)" , "Advantages" , "One's valuables" .)