Your desire for a typewriter shows admirable intentions but true creativity can never flourish within the prison of artificiality that is modern technology. If you want to touch greatness as a writer, the best thing you can do is restrict yourself to a twig and soft clay tablets. (Don't worry, they will harden.) I have owned a number of typewriters from an Underwood No.5 to IBM's Selectric II so I know whereof I speak. Now go forth and sin not.
As an aside, please note that almost any key, including backspace, will probably but not necessarily function as an Enter key on this site. It seems to validate the point that I was making above in jest. How confusing modern life is.