She might have pointed out that Pearl and Peony could have been given ready-made rather than custom dresses in order to budget for Cinder's as well. She might have pointed out that they would only wear their dresses one time too. She might have pointed out that, as she was the one doing the work, the money should have been hers to spend as she saw fit. But all arguments would come to nothing. Legally, Cinder belonged to Adri as much as the household android and so too did her money, her few possessions, even the new foot she's just attached. Adri loved to remind her of that

So she stomped the anger down before Adri could see a spark of rebellion.

(From Cinder, ch.2)