Grey Open Cardigans from 6pm.com
If you are on a limited budget, your best bet is this Bobeau Open Cardigan. It's a great piece, while not very pricey. In this price range, you can also consider this 525 America Open Cardigan. It's a product you'll love which also doesn't cost the earth. You might also want to consider this Open Cardigan. The price is very reasonable, but the effect on your wardrobe will be pretty fantastic.
If you're a bargain shopper, look no further than this BCBGMAXAZRIA Open Cardigan. This item doesn't cost a fortune, but absolutely indispensable in your wardrobe.