The box on the upper left is a custom box with a die cut cutout in it. It not only looks professional, but it gives a little window onto the soap so that you can see its color. That's the disadvantage of a soap box - not being able to see the soap that's inside it. The advantage is that it looks clean and finished and you have all the sides to put your text and information.
Another option that I'm putting in the "box" category is the soap on the bottom. While not in a box, it's completely wrapped like a Christmas present with a label added.