I would imagine there will be plenty of opportunities, that aren't on her birthday, to teach her that lesson. So why not save it for another time?

Make it a happy birthday, as the song goes, and look out for her by buying something that's not crap.

Then if she asks why you didn't buy her the whatever, then you can tell her, or show her, the research you did and why you didn't. That way you've got her something good and still taught her a lesson.