Simple/small don't belong in a sentence concerning shotshell reloading. Rustle up some funds and get a MEC 600 jr mark 5 reloader. It's AS simple and small as it gets.
Some will say get the lee load-all for shotgun. It's a flimsy plastic and aluminum toy that "kind of" loads shells.
Both are presses, requiring you to have SOME room to mount them to a table. In a pinch, you COULD mount them to a board that could be clamped to a kitchen table. Then put away when done.