A term policy, as the name implies, is good for a fixed number of years, usually ten. The premium is often guaranteed to stay the same for five years, but it goes up as you age. Term insurance is pure death insurance. That is, you pay the premium, and the insurance company pays off if you die. Unlike a permanent policy, this has no cash value.
Term insurance is relatively cheap.
The premium will depend on your age, your health history and whether or not you're a smoker. Try to buy it as part of a group plan such as a professional trade group or a college alumni association. As unpleasant as this thought is, the older you are, the greater risk that you will die. Permanent insurance is much more expensive, but it has the advantage of offering a level premium for life. In addition, much of the premium goes into an account on your behalf.