SaleAllDay365 via eBay offers this Motion-Activated LED Toilet Light for $2.59 with free shipping. That's tied with last week's mention as the lowest total price we've seen for such a light. (It's the best deal now by $5, 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.