Bonus!

bonus

Used as an interjection in reaction to a pleasant occurrence or receiving some benefit, often a surprising one. A: "And I got some ice cream for you, too." B: "Ooh, bonus!"

Bonus!

(ˈbonəs)
exclam. That’s great!; That’s good enough to earn a bonus! Bonus! That’s the best news I’ve heard in a long time!