TopperSun via Amazon offers the Minger 7-watt Light Sensing Dusk to Dawn Bulb 3-Pack in Soft White for $19.99. Coupon code "20Y3BA5A" cuts that to $15.99. Plus, Prime members bag free shipping. That's $4 off and the best price we could find. They feature a 600-lumen output. Deal ends April 20.