I make my own starch too, I use a spoonful of regular white wheat flour and water, cooked on the stove. More or less water depending how thick/stiff you want it. Spray on with a plastic spray bottle and let it set on the fabric for awhile to soak in.
I first heard about making it on one of the quilting forums, quilting gals really share. I only starch if I'm going to cut triangles. I like the cotton to be heavily starched so it doesn't stretch out of shape. I always have to wash the finished quilts but I like the crinkly look anyway.