值得 ( ) means "to be worth" doing something, and is often placed before a verb or a verb phrase. Note that it is used to describe whether an action is worth it and cannot be used to state that something is worth a certain monetary value. For that 值 must be used on its own.
值得 can also be used as an adjective - on its own, or following a verb phrase.
When expressing that something is not worth doing one can say something is either 不值得 or 值不得.