All perfect praise be to Allah, The Lord of the worlds. I testify that there is none worthy of worship except Allah and that Muhammad, sallllahu ‘alayhi wa sallam, is His slave and Messenger.
You are not obliged to return the price of the toy and the shirt that your uncle bought for you; such acts are common among relatives and require no compensation on your part. Moreover, when someone offers something to another person without requesting any compensation in return, then the recipient is not obliged to give him compensation for it.
The commentary of Jalaal Ad-Deen Al-Mahalli on An-Nawawi's Minhaaj At-Taalibeen reads: “When a person offers a gift to someone regardless of whether or not he specified a compensation, then there is no compensation required of the recipient if the gift-giver is of a higher (social) status, and the same applies when the recipient is of a higher status, according to the most likely correct view, and when he (the recipient) is also of an equal status, according to the view of our school, because this differentiation is not supported by the wording of the statement (of the Imaam).”
Allah knows best.