If you are on a limited budget, this J.Crew Tank will fit the bill. It's a foolproof choice, while not very costly. Another smart option is this Forever 21 Tank. While the price is rather reasonable, be sure that this piece will become a worthy addition to your wardrobe. You might also want to consider this Alexander Wang Tank. The price is very reasonable, but the effect on your wardrobe will be pretty fantastic.
If you're a bargain hunter, look no further than this Lanvin Tank. This item won't break the bank, but absolutely essential in your wardrobe.
If you can afford to splurge, then you absolutely must check out this Polo Ralph Lauren Tank. This piece seems costly, but it's top quality.