This is a beach purse that has a folded net which works as a trash bag when you suit it on the outside. You have to hang it from the buttons, this way the net won't fly away. The two components of the purse work as the trash bag lid, so every time you throw trash in the bag, you open it, throw it and finally, close it again, the trash will never come out. You can also set your trash bag with plastic bags, not only the net. 

You can watch the demonstration in the video below.