What is the value of a bicentennial 2 dollar bill?

Face value. Even though they don't circulate much, they're not really "rare"; they were a novelty when they were issued, and a lot of people stored them away thinking they would increase in value.

Fun fact: when NOBODY stores something away thinking it will increase in value, it does because it becomes rare; when EVERYBODY stores something away thinking it will increase in value, it usually doesn't since everybody's already got one... or a dozen.