Where to find sheet music for full orchestra/band?

I'm sure there is a better word for it, but I'm looking for a website to find the sheet music that has all the instruments in the song on it. Preferably something free. I'm want them so I can analyze them

Or is that pirating? I don't really know what proper etiquette is in this situation. I'm going to assume that, as with anything else, people want to be paid for their work.