Rich for life, practically -- I lead in commerce (8)
I believe the answer is:
prolific
'rich' is the definition.
(thesaurus)
'for life practically i lead in commerce' is the wordplay.
'for' becomes 'pro' (I've seen this before).
'practically' means to remove the last letter.
'lead in' suggests taking the first letters.
The initial letter of 'commerce' is 'c'.
'life' with its final letter taken away is 'lif'.
'pro'+'lif'+'i'+'c'='PROLIFIC'
(Other definitions for prolific that I've seen before include "Rich" , "Intellectually productive" , "Very fertile, productive" , "Plentiful" , "Abounding" .)