if you're in a thrifty mood, this Spiritual Gangster Tank will fit the bill. It's a fail-safe choice, while not very pricey. You might also be interested in this Sundry Tank. It's a product you're bound to love which also doesn't cost the earth. You may also want to look at this Vince Tank. This item is not expensive either, but it will make a difference in your wardrobe.
If you're in a Treat Yo' Self mood, then what you're looking for is this Michael Kors Tank. It's more expensive but worth your money. While you're at it, also have a look at this Akris Tank. Yes, this item is expensive, but it does not mean it's not worth it. Why not also take a look at this Dolce & Gabbana Tank. You won't regret the money spent!