I have been contacted about a project that involves either composing or sourcing music to be played in a shopping mall. (Three Hours)

Does anyone have any resources that might provide me some info on what it costs to secure royalties for existing music, or what it would cost to compose the music and then give exclusive rights to the mall?

I am sure it depends whose music you are trying to secure the rights to, but are there some general guidelines to follow?

many thanks!