SOLVED. Young adult: A book where you are the main character [s]

[Zara]

You have 2 best friends, and you go to a birthday party at the mall. There is a scavenger hunt where you try to find the birthday girl and you do a challenge when you find her. The goodie bags have iTunes cards and one of them also has an iPod nano. There are quizzes you have to take at the end of each chapter which tells you which chapter you're supposed to read next. The cover had a girl on it and the background was blue.

[Megan]

I looked up pick your own adventure books and this one deals with a party.

[Zara]

I found it! it's called Your Life But Better.

[Kris]

Thanks for the update, Zara. Here's the link - Your Life, but Better by Crystal Velasquez.