If you're a thrifty shopper, your best bet is this Halston Tank. It's a fantastic item, while not very pricey. Another nice option is this Bishop + Young Tank. It's an item you'll fall in love with which also doesn't cost too much. Or you can choose this Soybu Tank - be sure you'll be making a stylish addition to your wardrobe.
If you're looking to purchase a designer item, why not take a look at this St. John Tank - a great luxury choice.