if you're in a thrifty mood, your best bet is this J Valdi Cover-up. It's a fantastic piece, while not very costly. Another strong contender for your wardrobe is this Cover-up. While the price of this item is rather reasonable, it will surely attract a lot of attention. You may also want to look at this Laundry by Shelli Segal Cover-up. This item is not expensive either, but it will make a difference in your wardrobe.
If you're looking to purchase a designer item, then you won't be disappointed if you check out this OndadeMar Swimsuit. It's an expensive but smart option. While you're at it, also have a look at this Marc by Marc Jacobs Swimsuit. Yes, this item is expensive, but it does not mean it's not worth it. And one more item you might be interested in is this Gottex Swimsuit. 'Cause you deserve nothing but all the finer things!