The costs of trial offers are to be born by the company attempting to obtain subscribers or long term service. You don't have other people bear that cost for you, let alone product you have no legal right to profit off of.
I know, its a trial, how can their be profit. The profit is in the idea they will get a subscriber from the trial which is where the risk comes from. Apple should be taking the risk getting subscribers, not artist Apple chooses to play during the trial