How much do you give to your MIL for allowance to take care of your child?

We give certain amount for my MIL to buy groceries and do weekly marketing. The left over we let her to keep for her own use. My husband also give her monthly allowance but I never ask how much as I do not want to know and interfere. During festive seasons like chinese new year and mother's day, we will give ang bao as a token of appreciation.