What is the Value of a poor condition us 500 dollar bill?

Except for gold certificates, old bills have never been withdrawn so its value is at least $500. However the bill's condition could be more or less of a factor depending on the bill's date and possible series letter.

There's some generic information at the question "What is the value of a US 500 dollar bill?" but an in-person evaluation may be needed in light of the amount of wear.