Pigment (whatever makes the color) + Binder (something to hold it together) = Paint
Generally speaking, the quality and type of pigment determines the price of the paint. In fine art supplies, the old saying applies: you get what you pay for. Cheaper paints are cheaper because manufacturers use less expensive pigments to deliver color. However, does that mean you have to buy the best of the best to get great color in your watercolor work? My answer: No way! For everyday watercolor playtime, I say that anything goes!
I use a wide variety of watercolor brands and formulations, from cheapie pan paints to high-end tube watercolors. The Koi brand of watercolors, either in tube or pan form, is a great option for paint that is better than student grade but not as pricey as professional grade paints and it is one I would recommend. (For work you want to sell, I suggest using professional-grade paints since they are far less fugitive (fade-prone) than the cheaper versions.)
You can can get great color from even the cheapest of watercolors if you know how to work the color up out of the binder, especially when using pan (or hard) watercolors. So how do you go about doing that? Take a look...
Wet your brush and put a couple drops of water onto the pan of watercolor. The pan should be damp, not drowning in water. Work that water into the pan until the color clings to your brush like cream. Add water a drop at a time if it seems too dry. (I love white-bristled nylon brushes because they let me see how much color I have on the brush.) I don't add any more water until I get the color onto the paper. Once I get a nice, thick portion of paint loaded onto my brush, I add the paint to my paper, wash my brush, and use clean water to start pushing the color around. You can use this same method with cheap tube watercolors as well. Remember cheaper watercolors mean less pigment so if you add too much water, you are diluting that pigment even more.
Look at the difference in color brilliance when using far less water to get the paint up out of the pan. Example 1 uses a "typical" amount of water and if you want a pretty pastel look, then that's how to proceed. If you want more intense color, however, use a lot less water initially. This is how I begin my bright and colorful watercolor backgrounds. Next week, I'll detail how I blend colors without getting mud. Stay tuned and keep those questions coming!