Yes, you can use store-bought yogurt with live active cultures as a starter for making homemade yogurt. Look for plain non-dairy yogurt with "live active cultures" listed in the ingredients. Also, make sure to check the expiration date to ensure the yogurt is fresh. When you use a small amount of store-bought yogurt as a starter, it helps kick-start the fermentation process and ensures that your homemade nondairy yogurt develops the proper texture and flavor.