If you're on a thrifty budget, your best bet is this Joan Vass Tank. It's a wonderful piece, while not very pricey. Another strong contender for your wardrobe is this Caroline Rose Tank. While the price of this product is rather reasonable, it will surely attract a lot of attention. You may also want to look at this Champion Tank. This item is not expensive either, but it will make a difference in your wardrobe.
If you can afford to spend a little more, consider buying this Equipment Tank. While the price is very reasonable, this item is an easy wardrobe update. You might also be interested in this Misook Tank. It's an attractive option both price and quality-wise. Take a look at this Natori Tank too! Great value for your money.
If you're looking to purchase a designer item, then what you're looking for is this C/Meo Tank. It's more expensive but worth your money.