Wal-Mart is selling sidewalk lights, small for $2.00, large $4.00. They contain a solar cell about 1.5 inches square, a AA sized nickel cadmium battery, a photo cell and a small circuit board with a couple of resistors on it. They have a Westinghouse label on them.
I found them in Wal-Mart # 1001, today Feb. 8, 2011.
FYI