Haphazardly put South African currency in something small (2,6)
I believe the answer is:
at random
'haphazardly' is the definition.
(I know that haphazardly can be written as at random)
'south african currency in something small' is the wordplay.
'south african currency' becomes 'rand' (South African's currency is the rand).
'in' means one lot of letters goes inside another.
'something small' becomes 'atom' (atoms are very small).
'rand' inserted inside 'atom' is 'AT RANDOM'.
'put' acts as a link.
(Other definitions for at random that I've seen before include "unplanned" , "Casually" , "Without method or conscious decision" , "Haphazardly" , "willy-nilly" .)