How Much Is A 1926 Buffalo Nickel Worth?

Yeah.. pics would help.

Here is a link you can use to compare your coin to for grading
http://www.buffalonickels.us/grading.html
www. Buffalo nickels dot us slash grading dot html

According to Numismedia (a general price guideline):

Good (G4)- $1
Most details can be discerned, but will have a lot of wear. Some of the lettering will be merged with the rim in certain spots.

Very Good (VG8) - $2
Hair is flat, rays have weak spots, part of motto is weak, but with a complete rim.

Fine (F12)- $4
Hair bordering face is weak, slight wear on hair of the neck and the bun, and rays show a trace of wear.

Very Fine (VF30)-(VF20)- $6
Hair details bordering face weak, upper hair wave has light wear, hair by the ear area is worn, but single strands discernable. A VF20 will show a little more wear on above features.

Extra Fine (EF40)-(EF45)- $12
Hair has slight flatness on high points, but most hair strands separated. The face and lower neck lightly worn. A EF45 will show a smaller amount of wear on the above features.

Almost Uncirculated (AU50)-(AU58)- $20
Slight traces of wear on cheek, neck, hair around ear, and forehead; high points only. In AU58, only a slight trace of wear will be evident above the ear, and must not be confused with weak strike. Also, look for traces of slight wear on the rim and reeding; a hint of brief circulation.

Mint State (MS60-MS70)- $32 and up

Is there any letter under the FIVE CENTS on the nickel? a "D?" an "S"?

Worth a lot more if there is an "s" on the bottom of the coin under the buffalo.
Off the top of my head I believe the 26 s has the lowest mintage of the series.