Old-fashioned advice is to take them in exchange for money or goods (6)
I believe the answer is:
redeem
'exchange for money or goods' is the definition.
'old-fashioned advice is to take them' is the wordplay.
'old fashioned advice' becomes 'rede' (rede is an archaic word for advice).
'is to take' means one lot of letters go next to another.
'them' becomes 'em'.
'rede'+'em'='REDEEM'
'in' is the link.
(Other definitions for redeem that I've seen before include "Recover from the pawnshop" , "Save or cash in" , "rescue" , "Make good" , "Make amends (for)" .)