I really disagreee with this. If you become massively sucessful on a myspace/google/facebook level then perhaps. But has pg bought yombinator.com? Where does dig.com take you? What about gamil.com? twiter.com? micorsoft.com?

Forget about the misspellings, you're not going to lose a lot of traffic to them, people will soon realise they're in the wrong place. Save your money for better things like advertising and servers.