Shareware?

That sounds a bit like shareware to me. While I like the idea of it, I would not feel happy depending on voluntary contributions to run a software business, since they are something that can come and go. For a business model, I prefer the idea of selling something that people would not have if they didn't pay for it. (Of course, free software has shown often enough by now that it can be sustainable even when it isn't a sustainable business model).