How should I tell my mom i need $120 for the metronome I broke?

And how do I tell the band teacher I broke it? I was walking to my chair in band, when my bag must've bumped into the stand that the metronome was on, causing the wires connecting the battery to it to break. I guess it's unfixable because the teacher was sort of upset, since she was talking about how much it cost and such. How do I tell her I broke it? And is there ANY quicky ways to make money so my parents don't have to pay??? Thanks!