Unifun via Amazon offers the Unifun 24-watt LED Grow Light for $16.99. Coupon code "RZK5FPYK" cuts the price to $14.99. Plus, Prime members bag free shipping. (Non-members can spend $49 or more to qualify for free shipping; otherwise, shipping costs $6.87.) That's $2 under our July mention and $13 below the lowest total price we could find for a similar bulb elsewhere. It aids in the growth of plants and features a 50,000-hour lifespan. Deal ends September 30.