If you can’t spend much, your best bet is this Forever 21 Tank. It's a great item, while not very expensive. In this price range, you can also consider this Tank. It's also a popular item and won't break the bank. Or you can choose this Chaser Tank - be sure you'll be making a stylish addition to your wardrobe.
If you're looking for something in between pricewise, look no further than this 3.1 Phillip Lim Tank. This item won't break the bank, but absolutely deserves a spot in your wardrobe. Also take a look at this Courreges Tank. It's an attractive option both price and quality-wise.
If you can afford it, then you absolutely must check out this Marni Tank. This item seems costly, but it's well worth it.