If you are on a budget, your best bet is this Free People Tank. It's a popular piece, while not very expensive. Another smart option is this Soprano Tank. While the price is competitive, be sure that this product will become an excellent addition to your wardrobe. You may also want to look at this Lush Tank. This item is not expensive either, but it will make a difference in your wardrobe.
If you're looking for an item in the middle of the price range, check out this Ming Wang Tank. While the price is very reasonable, this product is an easy wardrobe update. You might also want to look at this Show Me Your Mumu Tank. It's an attractive option both price and quality-wise. Check out this Willow & Clay Tank too! Great value for your money.