Another linear regression question I am working on compares the price of biscuit mix to the number of boxes purchased.

My equation is y = -119.17 + 301.01

I know my slope is -119.17, but what does this represent if x is price and y is the number of boxes purchased.

And then my y-intercept - this would be (0, 301.01), but what does this represent?? Because it doesn't make sense - x represents price and y represents number of boxes purchased, so that would be at $0 cost, 301.01 boxes would be purchased??? That doesn't make sense.....please help!!