I bought some sound pack that had music.
Problem with music is same as with characters, for game you need matching set of more than 2-3 songs (or characters), and it need match your game theme. So make focused sets of music, rather than one song for each collection.
And yes, music needs to be personalized for game, also sounds should match the music style. So hiring sound person is usually better than buying something from market, unless its set of matching songs and sounds.