Best free painting program?

I've search the internet for so long to find a free painting program, and no luck so far. It's horrible having so many ideas on what to make, and having no way to do it. I'd like something like Photoshop, I want to be able to make my own characters, and if mess up on a stroke, I can move it around and stretch it out to make it perfect, so I don't have to erase it. I can't find anything like this, so if you know where I can find something similar to what I'm asking, that'd be great. And also, I've already used the online paint feature from onemotion.com.