If you're an Amazon Alexa user looking for something cheap, then Sengled leads the way with a smart floodlight that can pair directly with the Echo Plus or the Echo Show -- if you don't have one of those, you'll need the Sengled hub plugged into your router. You'll find those bulbs on Amazon in a two-pack that costs $18.
Sengled makes floodlights that change colors, too (and obviously, so does Philips Hue). But if it's a color bulb that you want, I say it's worth it to go with Lifx, an Australian startup that routinely aces our color quality tests with bold, bright shades that look terrific. The company's lights all use your Wi-Fi network to talk directly to your router, so they don't need a hub, they come with an excellent, full-featured app and they're compatible with Siri, Alexa and Google Assistant (and IFTTT) right out of the box.
A color-changing Lifx floodlight costs $30 at Amazon. That's not cheap, but Lifx floodlights are also a few hundred lumens brighter at peak settings than any competitor we've tested to date. Couple that with the color quality, and you're looking at a very worthy upgrade pick.