1928 $50 bills weren't issued as silver certificates. Please check the wording across your bill's top front; then see one of the following questions:"What is the value of a 1928 US 50 dollar Federal Reserve Note?""What is the value of a 1928 US 50 dollar gold certificate?"
1928 $50 bills were issued as gold certificates and as Federal Reserve Notes but they're not the same. Please check the wording across your bill's top front as well as its seal color*; then see one of the following questions: "What is the value of a 1928 US 50 dollar Federal Reserve Note?""What is the value of a 1928 US 50 dollar gold certificate?"* Gold certificates have gold seals and FRNs have green seals.
"A" is the highest series letter for 1928 $50 Federal Reserve Notes. "K" is most likely the Federal Reserve District letter. The series letter, if any, on US bills is next to the date. Please see the question "What is the value of a 1928 US 50 dollar Federal Reserve Note?" for more information on values.
A red ink 5 dollar bill is currently worth about $20 is good condition or about $50 uncirculated
There were no 1928 A $1 United States Notes printed, only 1928 "plain". If that's what you have it's worth $20 to $50 retail, depending on how worn it is.
I can't find a listing for a 1928-A certificate. If the "A" isn't located right next to the date then it is something other than a series letter. A standard 1928 gold certificate can retail for $250 to $750 so I would advise having your bill appraised to be certain of its value.
If very worn, $250; if nearly new, $750.
There were no 1928-J $50 bills issued. The series letter is right next to the date, so you should either see 1928 or 1928-A. Are you instead looking at the letter inside the circular seal? If so, that indicates the issuing Federal Reserve district and not the series. In any case, there are 3 different varieties of $50 note from 1928. A list of prices is available at: http://www.uscurrencyauctions.com/$50notes.htm
Your United States Note is worth $20 to $50 retail, depending on how worn it is. 1928 was the last time $1 bills were printed as red-seal United States Notes.
50-200 or so
$50
The value of a 1929G two dollar bill varies by circulation. A heavily circulated bill has very little additional value. An bill in good condition is worth about $10. A fully uncirculated bill is worth around $50.