Whoever bought some goods, took some things out of them, then offered the goods for sale and said that they bought the goods for such and such, it is Wajib (obligatory) on them to declare what they took out of these goods. It is not permissible for them to conceal this because doing so involves
telling a lie and deceiving the purchaser. On the other hand, they may offer these goods as if they were new and then sell them for a bargain price without mentioning the price for which they bought them or the things that they took out from them.
May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.