I'm gonna guess that it was made between 1960 and 1975. It is a mishmash of Sheraton (??) style and Let's Appeal to the Ladies style (those draw pulls). (though now that I've thought about it, maybe those pulls were added later.)
This isn't a place to ask value but just offhand I'd say that there are people who would pay a little more than you did for it and there are people who would not pay anything for it.
Martinsville made some decent things but this is just a reproduction antique-ish piece in a style that was in demand for awhile but isn't so much now. It's not considered a mid-century design even though it was made around that time. But if you love it, that's great--you got a useful desk for $23. That's something!
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