2012-boutique via eBay offers this 14-LED Arrow Mirror Turn Signal Light in Yellow or Red for $1.06 with free shipping. (Cell.Expert via eBay charges about the same.) That's tied with last month's mention and the lowest total price we could find by $4, outside of other eBay sellers. These lights have a lifespan of 50,000 hours.
Note: Allow up to eight weeks for delivery.