What is the value of a 1926-s buffalo nickel?

This famous design is called either a buffalo nickel or an Indian head nickel; both names are about equally common.

Look on the back under the Words FIVE CENTS for a tiny letter. That's the mint mark that tells where the coin was made. Retail values as of 09/2008 are roughly:

No mint mark (Phila.) : $1 if very worn, $6 if moderately worn, $10 with almost no wear.

D (Denver) : $8 / $25 / $130

S (San Francisco) : $17 / $90 / $600, plus or minus.