What is the value of a 1929 US quarter?

Look at the bottom of the pedestal on the left side of Miss Liberty's foot ("left" as you see the coin; i.e. her right foot). There may be no letter, or a small D or S. The M on the other side appears on ALL standing Liberty quarters and is the designer's monogram.

Numismedia lists the following approximate retail values as of 12/2012:

No mint mark:

Very worn condition - $9

Moderately worn-$13

Slightly worn- $32

Almost no wear - $76

Uncirculated - $130-2700 depending on quality

"D" mint mark:

Very worn condition - $5

Moderately worn - $13

Slightly worn - $37

Almost no wear - $79

Uncirculated - $145-8000

"S" mint mark:

Very worn condition - $9

Moderately worn - $13

Slightly worn - $32

Almost no wear - $79

Uncirculated - $140-2000