Flat fee for 15 minute song for video

by Gavin Bunn
(Wichita, KS, USA)

Flat fee for 15 minute song for video

I wrote a 15 minute song for a video and I don't know what I should charge for it. So far I know that I will be charging a flat fee and then after so much sales I will get a percent of each sale. The song is an instrumental and a good one. The client is very happy with it but I don't know what to ask for up front. Can any one way in on this?