If you can’t spend much, your best bet is this Io Ivana Omazic Tank. It's a terrific item, while not very expensive. In this price range, you can also check out this Sundry Tank. It's also a popular item and won't break the bank. You might also want to consider this Monrow 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, you're in luck with this Nic+Zoe Tank in stock and waiting for you. You are guaranteed to fall in love with this piece. Another smart option is this Rebecca Taylor Tank. It's an attractive option both price and quality-wise. Alternatively, opting for this Fabiana Filippi Tank is a nice choice as well!