If you are on a tight budget, your best bet is this Joan Vass Tank. It's a terrific piece, while not very expensive. Another strong contender for your wardrobe is this Caroline Rose Tank. While the price of this item is rather reasonable, it will certainly 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're looking for something in between pricewise, why not check out this Joan Vass Tank. While the price is very reasonable, this product is an easy wardrobe update. It's also worth checking out this Misook Tank. This piece is extremely popular and, just as importantly, not too pricey. Take a look at this Natori Tank too! Great value for your money.
If you want to splurge, then what you're looking for is this C/Meo Tank. It's more expensive but worth your money.