SaleAllDay365 via eBay offers this Motion-Activated LED Toilet Light for $2.56 with free shipping. That's slightly below last week's mention and the lowest price we've seen for such a light. (It's the best deal now by $3, excluding other eBay vendors.) It cycles randomly through eight colors (15 seconds per color, 120 seconds per total cycle) and requires three AAA batteries (not included).
Note: This item ships from mainland China and may require two to seven weeks for delivery.