i recently purchased two bathing suits from target. the bottoms fit fine but the top is huge! i am quite thin and small chested. how can i fix them!

Get two different sizes and put them together. The price is right. Donate the miss sized suit to Unique. Somebody will have the opposite problem and be happy to get your donation.

Exchange them, or go to a tailor who is able to fix that sort of thing.

Exchange the top for a smaller size?

the first thing that comes to mind is just to take back the tops and get smaller ones...