She's beautiful, like her mother, but perhaps expensive (5)
I believe the answer is:
pearl
'she's' is the definition.
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for pearl that I've seen before include "Precious jewel from the oyster" , "Object of great worth" , "Drop" , "prized example" , "Precious stone from shellfish" .)