Yes No?
I would say no. For large stores no, but for smaller stores yes…
If your parents agree, you can. It is questionable whether the shop will accept it. The seller can't know if your parents allow it.
Section 110 of the German Civil Code basically says the following: If you receive money either from your parents or from anyone else with your parents' consent, at your free disposal, you can effectively conclude contracts with this money without your parents being involved in the specific legal transaction ( that is, the specific contract).
It doesn't matter how much pocket money you get. It doesn't matter how expensive it is. It is only important that the funds (= the money) that you use for the purchase have been given to you by your parents (or by third parties with the consent of your parents) either for the type of legal transaction or even at your disposal. Therefore, you can save your pocket money (but also other money, e.g. Birthday gifts) and then buy something that is significantly more expensive than the monthly pocket money.
Important: As a minor, you can't effectively make installment purchases. So, for the contract to be effective from the start, you must have paid the money in full. If you want to make a purchase in installments, you need your parents' consent again.
