If you want to draw digitally, all you need is a painting program, of which there are many free ones. Most people LIKE having tablets, but you don't NEED one to start drawing. There was a really long time there I drew 100% with a mouse when I first started using photoshop back in middleschool, and I know there are people with decent comics who also draw using the mouse, so if you want the absolute bare minimum, you can nix the tablet. It just makes drawing on a computer feel more natural and makes stuff like line tapering, among other things, far quicker and easier.
If you want to go traditional, you can totally just draw on copy-paper with whatever you have and then either scan or take a photo of it (although I'd be careful with taking a photo cuz it can be really tricky getting the pictures taken just right so that it's not obvious you're just taking pictures) You'ld still want to have a painting program so you can easily crop and resize things. I haven't tried any of 'em so I can't vouch for how good they are, but Gimp, Krita, and MyPaint are a couple. Hopefully some other folks will comment with other free paint programs you could test out cuz it's really about testing around to see which one feels right for you.
SO TL:DR. Exactly @Wishjacked's first line there, something to draw on and something to draw with. For digital that can be a minimal as just a painting program and a mouse, for traditional it can be as minimal as copy-paper and pen/pencil with a good way of getting it onto the computer. There's no reason you couldn't make a decent comic with just that.