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 Allaah.
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.
Sheikh Muhammed Salih Al-Munajjid