You can, of course, buy high quality component ingredients and mix them yourself -- we sell two of the best: Winsor & Newton Acrylic Flow Improver and Liquitex Slow-Dri Fluid Retarder! However, most commercial paint additives are packaged with canvas painters in mind -- not in convenient dropper bottles and not in appropriate sizes. Even small bottles can easily cost over $10! AND then, you would still need to buy distilled water AND a dropper bottle and manually measure AND mix your ingredients.
Lasting-Flow™ simply provides convenience and consistency, and at a reasonable volume and price. Our 1/2 ounce dropper bottle of Lasting-Flow is designed for convenient use and storage with your existing miniatures paints and provides enough paint additive for a very long time.(Conversion charts indicate over 1000 full drops/ounce - and I rarely use a "full drop"!)