Staples offers the LED Solar Rock Landscaping Lights 4-Pack, model no. 50-21, for $14.99. Plus, Staples Rewards members bag free shipping. (Not a member? It's free to join.) That's the lowest price we could find by $3, although we saw it for a buck less in July. Each one measures 4.5" x 4.5" x 4".
Reviews on Amazon for this light are pathetic, do not buy!