Please post a new question with the bill's denomination, date, and what letter if any is next to the date.
This means that that note is a replacement to a damaged note. These usually have a value above face value but not much more. For example you might get $1.50 or $2 for a star $1 note.
A denomination is needed. Please look for questions in the form "What is the value of a 1928 A US [denomination] dollar Federal Reserve Note?" for specific information.
The green seal indicates that it's a Federal Reserve Note. Please see the question "What is the value of a 1928 US 5 dollar Federal Reserve Note?" for more information.
The green seal indicates your bill is a Federal Reserve Note. Please see the question "What is the value of a 1934 US 5 dollar Federal Reserve Note?" for more information.
The green seal indicates your bill is a Federal Reserve Note. Please see the question "What is the value of a 1934 US 5 dollar Federal Reserve Note?" for more information.
What is the value of the shortest note
Unless it's an error note, any US bill dated 2006 is too new and too common to have any extra value.
About $3.
Could you check your bill again? A red seal would indicate that your bill is a United States Note; the first $2 FRNs were dated 1976 and have green seals. If you have a US Note, there's more information at the question "What is the value of a 1928 US 2 dollar bill?"
The green seal indicates that your bill is a Federal Reserve Note. Please see "What is the value of a 1928 D US 5 dollar Federal Reserve note?" for more information.
The largest denomination of currency the US prints today is the $100 bill.
Your bill is called a United States Note rather than a promissory note. There were eight different subseries within the 1928 series date; please see the question "What is the value of a 1928 US 2 dollar bill?" for specific information about values.