You can choose to get cheap paint from a dollar store for your painting experiments, but these aren’t the best way to experience watercolor techniques. Cheap paint tends to contain a lot of fillers, so they appear chalky and crumbly when dry. They also absorb water quickly, making them difficult to blend. This makes it a struggle to achieve a technique like the variegated wash, which depends on the colors naturally blending together on the page.
It’s best to invest in higher quality student-grade watercolor paints instead, such as the Cotman paints from Winsor & Newton. These paints are very pigmented compared to the cheaper brands, and will work the way you need them to. Plus you can often find a basic set for a pretty good price!