if you're in a thrifty mood, your best bet is this Beyond Yoga Tank. It's a great item, while not very pricey. Another strong contender for your wardrobe is this Nike Tank. While the price of this piece is not very high, it will surely attract a lot of attention. Or you can choose this The Upside Tank - be sure you'll be making a stylish addition to your wardrobe.
If you're looking for something in between pricewise, look at this Misook Tank. While the price is very reasonable, this product is an easy wardrobe update. You can also consider this Fuzzi Tank. It's an attractive option both price and quality-wise. Alternatively, opting for this Misook Tank is a great choice as well!