The open front cardigan is the perfect coverup for off-duty days. A chunky cardigan will work very well with a basic t-shirt and jeans.
If you're after a thrifty option, consider buying this Brave Soul Open Cardigan. It's a popular item for a reasonable price. Another strong contender for your wardrobe is this Brave Soul Open Cardigan. While the price of this item is rather reasonable, it will certainly attract a lot of attention.