The difference between lottery and sweepstakes primarily lies in the requirement of purchase and chance. Lotteries typically require participants to buy a ticket for a chance to win cash or prizes, making them a form of gambling regulated by law. In contrast, sweepstakes do not require a purchase; participants can enter for free, relying solely on luck to win prizes. Understanding the difference between lottery and sweepstakes is essential for consumers, as it affects eligibility, legality, and the overall experience of participating in these promotional activities.