Are online games that advertise extravagant gifts in exchange for games of chance considered gambling (maysir) or permissible (halal)?

If playing involves a financial stake from the participant, then it is gambling (qimar) and a game of chance (maysir), because in gambling, a person alternates between gain and loss. However, if the playing is without a financial stake, then there is no harm in it, provided that the games themselves are permissible.