Zero percent interest is a promotional offer where no interest is charged on a loan for a limited period, making it a popular choice in retail financing. Borrowers pay only the principal during this timeframe, reducing the immediate cost of credit. However, interest may begin accruing after the promotional period ends, sometimes at higher rates. Zero percent interest deals can be effective for budgeting, but borrowers need to ensure they understand the terms and have a repayment plan to avoid future debt.