Honestly, in the several years I've been on the net, I can only recall two times I sent anyone a gift. One was to someone I've known for 3 years and trust, and the other was a present for my boyfriend. Neither one of them were underage. :P
If a parent or guardian of a minor does not want said minor to learn, practice, or study magic and an unrelated adult gives them a random gift, say of a book on magic, the parent/guardian's rights are being infringed upon. As a minor, you have the rights that your parents say you have, you don't have many rights of your own (beyond abuse cases, etc). No, it is not abusive, mean, or nasty for your mommy or daddy to tell you no to the things you want. That's when mommy or daddy is showing they love you and actually care about what kind of person you grow up to be.
If they aren't aware of your practices, you don't need to be buying anything until you tell them and get approval or else you become 18 or get emanciapated. If you are unwilling to do any of these things, you don't really need anything you think you need.
I also won't spend any money on some random kid on the net that I don't know. It's my hard-earned cash, why do you need it?