Buying and selling on a Sabbath is not what God would smile on, and advertisement would be likewise undesired.
It is friend. Some places you have examples of people running their businesses on Sabbath and donating the proceeds to the church or a church program of sorts...all in an attempt to keep the Sabbath Holy. We have six days to this sort of business.
I will let you let the Holy Spirit tell you what is wrong or right about this. What does the bible say? What does Jesus Christ say? How are you impressed?
No, no business on Saturday and no advertising. There are six other days of the week to do this.
Is it necessary? and are the proceeds going to God, or self? Is it desecrating the temple?
God will judge them for whatever intent they had when they made the music as well as when they sold it. If you really want to know more about it you should talk to the member(s) to find out their motive(s) and go from there.
NOT ONE OF US IS THE JUDGE. GOOD THING GOD LOOKS AT THE HEART AND THE INTENT AND NOT WHAT WE SEE. PHARISEES AND OTHER SABBATH FANATICS TRIED FRAMING JESUS FOR BREAKING THE SABBATH.