All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.
It is impermissible to sell human body parts. The Haashiyah of Ibn ‘Aabideen reads, “The human being is honored in the religion even if he is an infidel. It is unlawful to subject the human being to selling and buying like inanimate objects; such actions are an offense and dishonor to the human body, i.e. it is impermissible and the same applies to any part of it, and the author of Fat-h Al-Qadeer stated that it is invalid.”
Therefore, it is impermissible for you to sell human bones under any given circumstances. Even if you have bought these bones legally for a lawful necessity, such as buying them to use them in anatomical studies and there was no other way to obtain them except through buying them; still this does not make it permissible for you to sell them. The fact that the rest of the students will buy the bones from others anyway does not make it permissible for you to sell the bones to them.