If you want to recreate Kate's casual look, you'll want to begin with a yellow sweater like this one for $29 from Victoria's Secret (see a couple of alternatives HERE and HERE). I realize it's not cropped, but it will give you a similar look on a budget. Click on any of the photos to purchase the items shown in this post.
Pair the above sweater with a simple white tank from Charlotte Russe ($6.50), flare jeans from American Eagle ($49.50), and wedges from DSW ($29.94).
Complete the look with some similar accessories and you're all set!