There are four types of ads you might see in City Girl Life.
Loading ads appear when you load the game.
Cafe ads appear when you leave The Grounds to return to your apartment or visit a friend. These ads play only once an hour, no matter how many times you leave The Grounds.
Idle ads appear when your game has been idle for three minutes. These ads will continue to play until you return to the game and vanish as soon as you move the mouse.
Video Lotto ads play when you choose to watch them. Watching these ads rewards you with free spins on the Video Lotto. You can find the Video Lotto by clicking the blue present icon in the top right of the game window.