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 is His slave and Messenger.
As long as your parents' money is not purely Haram, but rather mixed - as you have mentioned - then the most correct view is that it is permissible to deal with the owner of mixed money, with the dislikeability that could be more or less depending on the amount of the unlawful (Haram) money. This dislikeability is negated with the need to those expenses, and accordingly it is permissible for you to take the tuition fees from your parents, and likewise expenses for additional lessons, and asking them for money to buy some of your needs, even if they are not necessary.
Allah knows best.