Money demanded for release of answer held in memory (6)
I believe the answer is:
ransom
'money demanded for release' is the definition.
(I've seen this before)
'answer held in memory' is the wordplay.
'answer' becomes 'ans' (abbreviation for answer).
'held in' indicates putting letters inside.
'memory' becomes 'ROM' (ROM is an example).
'ans' put into 'rom' is 'RANSOM'.
'of' acts as a link.
(Other definitions for ransom that I've seen before include "Money demanded for the release of a captive" , "Kidnapper's payoff" , "Go beyond (a level)" , "Fee for kidnap release" , "Payment, eg to kidnapper" .)