If you're in a thrifty mode, your best bet is this J.Crew Sweater. It's a fantastic item, while not very expensive. Another nice option is this J.Crew T-shirt. While the price is competitive, be sure that this item will become an excellent addition to your wardrobe.
If you're looking for an item in the middle of the price range, take a look at this J.Crew V-Neck Pullover. While the price is very reasonable, this piece is an easy wardrobe update.