a colleague of mine wants me to think and record a bassline, a melody that goes with a piano part and then it can be used alone with vocals. it's probably 20 to 35 seconds of music but it requires some analysis of the song and the chords. she keeps asking how much will it cost. both of us have no idea how much i should be paid because i am a gigging bassist and she is a dj. how much should i ask?