Small crease? Don't be too expansive (6)
I believe the answer is:
scrimp
'don't be too expansive' is the definition.
I can't judge whether this definition defines the answer.
'small crease?' is the wordplay.
'small' becomes 's' (abbreviation - e.g. clothes size).
'crease?' becomes 'crimp' ('crimp' can be a synonym of 'crease').
's'+'crimp'='SCRIMP'
Can you help me to learn more?
(Other definitions for scrimp that I've seen before include "Pinch and save" , "Keep short" , "To pinch pennies" , "Skimp, stint" , "Watch the pennies" .)