If you are on a tight budget, consider purchasing this Madewell Tank. It's a popular piece for a good price. It is also worth taking a look at this O'Neill Tank. It's an item you're bound to love which also doesn't cost the earth. You might also want to consider this Leith Tank. The price is very reasonable, but the effect on your wardrobe will be pretty fantastic.
If you're looking for something in between pricewise, consider purchasing this Beyond Yoga Tank. While the price is very reasonable, this product is an easy wardrobe update. It's also worth checking out this Nic+Zoe Tank. This item is extremely popular and, just as importantly, not too pricey. And do check out this Misook Tank! It's a very popular item and good value for money.
If you have enough to afford it, then you absolutely must check out this Marni Tank. This product seems costly, but it's well worth it. While you're at it, also have a look at this Misook Tank. Yes, this item is expensive, but it does not mean it's not worth it. You can also take a look at this Eileen Fisher Tank. You won't regret the money spent!