In the song "New York City Girl", the singer tells the New York City Girl that "you should know the score by now". Meaning she shouldn't be so naive. She shouldn't think that love is going to be like the Broadway shows, i.e fairy tale like. She's had enough bad experiences to know better, "to know the score by now"!
Someone who is addicted to obtaining money and building wealth. A money addict and fanatic. Breadheads often work more than one full-time job, and some even participate in illicit activities to "obtain the bread".