Bubble hair dye is essentially a foam-based hair coloring product, often originating from Korean beauty brands. It's designed for easy, at-home application, much like shampooing your hair.
Because it's designed to be easy to use at home, you can expect ease of application. Korean brands like Etude House, Tony Moly, Holika Holika, and Mise En Scene are popular for bubble hair dyes. The price point is generally affordable.