I come from a long line of this and that kind of cooks. Many recipes don't have any measurements. Such is the case for these sloppy joes.
I've made these Sloppy Joes for picnics, pot lucks, showers and funerals. People usually really like them. When my son was young, he used to have a lot of fun waiting for someone to say they like them and then he'd tell them they had Diet Coke in them. He liked to watch the surprised look on people's faces!
Brown some hamburger. You can brown a veggie with it if you want (onions, peppers, celery). When the burger is good and brown, drain the fat and season the meat with something. (salt, pepper, maybe some BBQ spice or a little garlic powder). Add equal amounts of ketchup and some kind of diet pop (Coke, Pepsi, or Dr. Pepper, or even root beer - just make sure it's diet). Add one drop of mustard if you only cooked a pound of burger, more mustard if you cooked more. Open the bag of brown sugar and grab about a golf ball size of a clump and mix it in with everything else. Simmer until it's thick. Serve on buns.