Praise be to Allah.
That is not permitted, because they are benefiting themselves and harming others. They offer a prize of a car or freezer, etc., and say that whoever buys such and such can take part in this competition, and we will draw one of the names, and if he wins he will get a car worth one hundred thousand or whatever. So the people rush to them and maybe ten thousand or twenty thousand customers come, but only one will win the competition and the rest will lose. Thus they harm the owners of other stores because the people rush to them and ignore the other stores which causes harm to the others.