For the record, I paid about $25 for a one quart bottle (at our somewhat over-priced local hardware store), but you only need an ounce or even less per gallon of spray. I've stopped measuring it and just add enough to make the liquid in the tank visible. It WILL stain clothing, tho, so don't get too rowdy with it! (Another added benefit is that you will know if you have inadvertently sprayed yourself.)
