i just had an idea i would like to share with you. maybe this is goining to be realized.
at the moment you have a button "buy" where you can include links to a webshop or beatport or whatever. but there is also a lot of creative commons licenced content on soundcloud offered by different users like netlabels or just musicians. since a while you can even search for cc-content on soundcloud. i think it would be a good idea to add a button called "donate" where you can include a link to paypal or similar that users can donate for free content. the fact offering free music does not make it worthless. also people might be interested in supporting free content if they appreciate it. i hope you will consider my suggestion and looking forward to.
thank you for what you are doing!