I am trying to apply a DataFormatString of {0:C} or $ {0:F2} to the ItemPrice of the GridView as recommended on page 116 of the book.
No matter what I do, I always get FOUR decimal places. Even Figure 4-13 on page 117 shows the final result page with four decimal places.

Any suggestions?

I got it to work correctly following a hint on the MS VWD support site: for the column(s) where you specify a DataFormatString also set HtmlEncode=False

Yes, it does work fine in other controls such as Label, as used in the final code for the example shown on page 122.