The cheapest term life insurance would be term life for one year. Since term life costs more per year based on the number of years you have coverage, the shorter your "term", the cheaper your life insurance policy.
However, term life policies usually offer coverage for a "term" of 10, 15, 20 or 30 years.
Other factors that impact your cost of life insurance include the amount of life insurance, the insurance company, and your age, gender, health, occupation, hobbies, lifestyle, tobacco use, driving record, and height-to-weight ratio among other factors.
Here's how you can learn more about term life insurance and compare rates.