This flowy chiffon skirt! I love it so much. It runs small, I usually wear a small and bought an XL. If you read the reviews the bigger sized only increase the length. I am 5'3" and the XL hit the floor for me. It has a stretchy waistband though so could fit someone larger than me I am sure.
This gold and white bodycon dress. Super cute, true to size.
Honerable mention to my wedding dress. Yes I bought my wedding dress on Amazon for a little over $50. It was beautiful, fit perfectly (I only needed to get it hemmed a bit), and I didn't care about getting sand and seaweed stuck to it because it was so cheap!