Why do I see so many different spelling of this word in my inbox?
Maybe because spam checkers weed out the correct spelling. I get that.
I think, though, that since it is so over used, and we could easily use
words such as "no cost" "for nothing" "you don't pay a dime" etc -
that the gimmicky spellings are a more powerful call to action than the
like spelling with the hiccups
You notice when someone has the hiccups, right?
Maybe you try harder to listen to them?
photo credit: http://www.geograph.org.uk/photo/153952