What is the worth of a 1928A one silver dollar?

Where are you getting the "A" after the date?

The value depends on the condition and where it was minted.

The best site for values is PCGS The Standard for the Rare Coin Industry... and you can also check eBay for what that coin is selling for.

RENEE- ON the 1928A {ONE SILVER DOLLAR) OR IS THIS A ONE dollar, { SILVER CERTIFICATE?? } ;;IF its paper money yes it will be a 1928A-IN PAPER MONEY ,but will be a silver certificate;;; { IF it's a coin -it will be a silver certificateON A COIN THE MINT MARK IS ON THE BACK SIDE UNDER THE WORD { ONE}, IT will have NO mark- Philiadeiphia;; A { D } FOR DENVER, :: OR A { S } - for san francisco;; Waiting for your reply;; Have a great night and a better tomorrow AND GOD BLESS:: F.B.E.