The y- intercept is 12, and it means the initial cost without games is 12 dollars.
The y-intercept is where the line intersects with the y-axis, or when x is 0. In this case, the y-intercept is 12. I’m guessing this is some kind of arcade problem in which it takes 12 dollars to get in, and as one plays more games, there’s an extra fee. So the y-intercept represents when someone has played no games and just paid the entrance fee.