If you're on a thrifty budget, your best bet is this J.Crew Crew-neck Sweater. It's a great product, while not very pricey. Another wonderful option is this J.Crew Sweater. While the price is not too high, be sure that this item will become a worthy addition to your wardrobe.
If you're looking for a happy medium, why not look at this J.Crew Blouse. While the price is very reasonable, this piece is an easy wardrobe update. Why not also check out this J.Crew Shirt. It's an attractive option both price and quality-wise.