What is the value of a 1979 quarter dollar?

Answer 1

I have a 1979 Quater with a filled in key letter (D) LOOK LIKE IT MAY BE A ERROR, IS IT WORTH ANY THING/ Worth saveing. has any one else got one of these Quaters?

Answer

1. QUARTER, just like it's spelled on the coin

2. MINT MARK, not "key letter"

3. SAVING, not "saveing"

Now that we're past basic spelling and terminology, you have a very common error called a filled die error. It happens when a bit of grease or crud gets into the little recesses on a die that form the letters and numbers when a coin is struck. Filled die errors are quite common, especially on older coins that used a smaller mint mark than current issues. They're interesting but are rarely worth much more than face value.