Complex sentence: Their first musical, "Tell it Like it is", which included the song "Pass it on", sold 2,500 copies, completely selling out the first run, it then completely sold out its second run of 100,000 copies as well.
Split into simpler sentences: Their first musical, "Tell It Like It Is", which included the song "Pass It On", sold 2,500 copies and completely sold out its first run. It completely sold out its second run of 100,000 copies as well.