How about: YOU may already be a WINNER!?
or:
"My Dearest Darling Miss Pringle", just to stir things up a little!?
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Actually "Dear" is the standard.
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Not mentioned but also acceptable is: To Whom It May Concern, as in

Webley Widgets
Sprockets Division
1234 Whataboutit Pkwy
Nothing AZ 85353

To Whom It May Concern:

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Standards also include:


Company Name
Address
City (2 Cap Letter State Code [no comma]) ZIP+4
Person's Name
Title and/or Department
(skip a line)
Dear Mr. So and So

or
My Dear Mr. So and So