Yay for me

http://www.urbandictionary.com/define.php?term=yay
check the 1st definition

Simply, it's an informal way of saying either I did something good and I want you to know about it or something good has happened to me and I'm happy about it.

I found a $10 bill on the street - yay for me!

Looks like I'm first in line for the promotion - yay for me!

You would use this only with your good friends.

Interesting. I don't think this is common in British English yet. But then, a slightly less elated expression would probably be more likely in BrE, in those contexts:

1. I found £10 in the street. ******. Now I suppose I'll have to go to the police station and hand it in.

2. Looks like I'm first in line for the promotion. Just my luck. Now I suppose I'll have to start going to al

Don't worry, Mr. P. I'll help you with those presentations. Just pay me in Newcastle Brown.

It's a deal.

(Only one thing: I may need a case of Jack Daniels in return, when I give them.)