Currently you can stream Dragon Ball Super: Broly through Starz. You can get Starz directly or through Amazon Prime Video with a free trial.
If you don't have STARZ and you don't want to get STARZ then our first recommendation is use the free trial! You'll be able to stream Dragon Ball Super: Broly then cancel before you get charged. But if you really don't want to subscribe then you can buy or rent Dragon Ball Super: Broly from platforms like Google Play Movies, VUDU and FandangoNOW for as little as $2.99, a great price.