Her plans unexpectedly change? (8)
I believe the answer is:
shrapnel
'change' is the definition.
(both can mean coins)
'her plans unexpectedly' is the wordplay.
'unexpectedly' indicates an anagram.
'her'+'plans'='herplans'
'herplans' is an anagram of 'SHRAPNEL'.
(Other definitions for shrapnel that I've seen before include "Pieces scattered after a shell explodes" , "Fall out from bomb" , "bursting shells" , "Bomb or shell fragments" , "Metal bomb fragments" .)