Our Daily Bleg: Spanish-Language Music, Please

From a reader named Joe McCright of Alexandra, La., comes the following bleg. Please help him out in the comments section. Past blegs can be found here; you can send your own bleg requests here.

I teach Spanish to kids in pre-K through 4th grade, and I play music of the Spanish-speaking world to expose them to aspects of the culture.

What specific artists and songs do residents of the Spanish-speaking world consider to be representative of a specific genre of music — e.g., tango, baladas, cumbia, etc.?

Moreover, I need free and legal music. Where do I go?

Addendum: This video of a marimba version of “New York, New York” sent in by commenter Pierre (thanks!) is fantastic. I think the N.Y. Yankees should bring these kids in to play after their victories instead of the old Sinatra version.