Selling products to children for more than the wholesale price

Can a Muslim sell products that he has purchased wholesale having a price ready-printed on them (e.g. canned drinks on special offers) at a higher price to others, in particular to Muslim children?

Praise be to Allah, and blessings and peace be upon the Messenger of Allah:

There is nothing wrong with increasing the price, because this is what trading and business are based on. But there exists the condition that this should not involve lying, cheating or hoarding something that people need, such as food staples, etc.