I just started playing Super Meat Boy, and loved the online collections of levels. After seeing some of them, I decided to create my own. Seeing that I am new to the game, I do not have many bandages, if I need those to create custom levels.
It's not exactly clear what you ask. How many bandages do you need? You need 20 bandages to be able to create your own levels. To learn 'how' to do it there are videos on the official SMB forum.