Oooooh a Quinceanera! How fun!
My first thought for red carpet and glitzy is a floor length prom-type dress... though not "poofy". More sleek.
Shape ideas here
, and here
Since you said bigger bust, I thought something with straps might be best for support.
While glitzy can easily be added on with costume jewelry, the dresses I think that look classy are satiny with only a small bit of flash on the actual dress. Yet they still say "red carpet", and you won't show up the girl of honor.
Of course, if you ARE hoping for a bedazzled dress, maybe something more like this?
(Note: I wasn't looking at prices. Just looking at shape and style for examples.)
You might be able to find some cheaper prom-type dresses out there seeing as prom season isn't until Spring. Like at David's Bridal or something. I saw some on their site for under $100. That's maybe not cheap
, of course, but I'm sure there are better deals out there.