What is the ruling on selling purchases to family members at a price higher than the purchase price, taking into account the effort and expenses, and is this increase considered permissible?

If the family's request for goods is merely an expression of desire, and you bought them for yourself, then you may sell them to them at any price, and you are not obliged to inform them of the purchase price unless asked, and then you must be truthful. However, if their request was an authorization for purchase, then they are obliged to take the goods and pay their original cost, and you are not permitted to increase the price on them except with their knowledge and consent.