Well, the good news is you already seem to have a pretty strong intuitive sense for how to balance your sounds (and also just how to write music that works). In that track you linked, only the saxophones really stick out to me as bad.
That being said, you can't get free saxophones that sound better than that; it's just not gonna happen. Anything that would sound better would take a lot of work, and that's work that someone would sell it for to make money on.