Is it permissible to organize a cultural competition to increase sales, where participation is open to anyone who buys a certain quantity of goods, and what are the Islamic legal conditions for such competitions?

Permissible cultural competitions that increase a Muslim's understanding (fiqh) or beneficial knowledge, or enhance their intelligence, are allowed. It is permissible to receive prizes from them, provided that the prizes are from a donor whose aim is to motivate competitors to learn. However, if the prize provider intends commercial profit, then the competition becomes a form of gambling (qimar), especially if participation requires purchasing a certain quantity that the participant does not need, for whoever enters it will either gain or lose.