If you're not planning on spending much, your best bet is this City Chic Tank. It's a terrific piece, while not very expensive. You might also want to take a look at this Missguided Tank. It's a product you'll fall in love with which also doesn't cost a fortune. You may also want to look at this Free People Tank. This item is not expensive either, but it will make a difference in your wardrobe.
If you're not the one to skimp on clothes, then you absolutely must check out this Joie Tank. This item seems pricey, but it's worth it. While you're at it, also have a look at this Rag & Bone Tank. Yes, this item is expensive, but it does not mean it's not worth it. And how about the luxurious Equipment Tank? Yolo, right?