"I stuffed everything in my bag"
Bella's Bag
Public DomainBella's Bag - Credit: JanSport
Plain Black Jacket
Public DomainPlain Black Jacket - Credit: Juicy Couture
 Bella's Wardrobe

The book does not specify what type of bag it is, but in the movie Bella uses a coppery/brown bag.  

Bella wears a black jacket with a hood, perfect for blending in with the crowd.