Fortune initially told after thirty seconds? (4)
I believe the answer is:
mint
'fortune' is the definition.
(making a mint is making a lot of money)
'initially told after thirty seconds?' is the wordplay.
'initially' says to take the initial letters.
'after' says to put letters next to each other.
'thirty seconds?' becomes 'min' (half of the word 'minute').
The first letter of 'told' is 't'.
't' after 'min' is 'MINT'.
(Other definitions for mint that I've seen before include "and 18 Down: Southern US cocktail" , "Grown in the herb garden" , "sweet herb" , "Flavour of the money-maker?" , "strike?" .)