Question: What is the ruling on competitions which are announced by some businesses in which they give prizes like a car and other than it and what is the ruling on participating in it?
Answer: “There is no harm in this with two conditions:
First condition: that the prices of the merchandise in this store do not rise
Second condition: that the one purchasing it has the intent of the merchandise, that is, that he will purchase it in any case.
If he is purchasing the merchandise for the prize, then this is not allowed because sometimes he will buy many things and he will not win the prize..
Questioner: However, from the rules of the competition is that he must purchase!
Shaikh: I understand. If you purchase it, do you do so for your need or for the competition?
Questioner: For the competition.
Shaikh: It is not allowed because sometimes you will buy 200 riyals worth or 300 riyals and you do not win. If you will purchase a product inevitably, like gas nowadays, where the gas station owner places a prize for gas and its price is the the same. You choose this station for the prize and you are not one in loss, then there is no harm in this because now either you are a winner or one who is safe. However, if you do not want to purchase it, for example, I heard that there are prizes associated with some milk cans. I heard that some people buy a 100 cartons or more, then pour them on the ground so that they can gain the card which has the prize! This is not allowed. Likewise, if the businessmen raise the price then it is not allowed because this person will purchase it for a greater price, so he will either be a winner or one in loss.
What is important is that we know these two conditions:
First: that the price of this merchandise is like the price of anything else in the market
Second: that a person purchases it for a need not for the prize”
[Taken from: Liqaa Bab al-Maftooh no. 203]
Faisal Ibn Abdul Qaadir Ibn Hassan