Us Weekly has affiliate partnerships. We receive compensation when you click on a link and make a purchase. Learn more! Sure, you could throw on a tee and a pair of shorts over your one-piece, but there’s something about a swimsuit cover-up that makes it feel like you’re on vacation. Amazon is making sure you’re not breaking the bank by providing plenty of options for under $30. They’re so good that we’re confused how they’re still in stock! Like everything you wear in the summer or on vacation, you want it to be lightweight and breathable, which is what we…