I have a project that I want certain colors of watercolor paints for and I thought it might be easiest to make the colors myself. I found two basic recipes that were the same except for one used glycerin and the other corn syrup. I chose the one with corn syrup and I found that recipe at Martha Moments.com. There are plenty of other sites out there for the same or similar recipes.
4 Tablespoons baking soda
2 Tablespoons vinegar
1/2 teaspoon corn syrup
2 Tablespoons corn starch
I'm not sure that I will ever buy watercolor paints again. They turned out really nice and they were super easy to make. My one and only complaint is they dry a bit grainy, but it's not a big enough problem to be a deal breaker for me!