What is the value of a 1942 US 5 dollar bill with a yellow seal?

Answer 1

Please take another look at your bill. There were no US bills dated 1942.

If it has a yellow seal and the words North Africa printed over the design, you have a special note printed for use by troops in that combat zone during WWII. That means it could have been printed in 1942, but the date on the front should say "1934 A" because all US bills carry series dates, not printing dates.

As of 05/2013, a North Africa overprint $5 bill would retail for $20 to $60 in circulated condition. Uncirculated ones are much less common and can bring $250 or so.