This box is perfect for when I bake a 6-inch or 8-inch cake. It came out to $1.62 each.
 
Get it here on my Amazon associates page, I get a small commission each time you get it here.
 
Kootek 15pcs Cake Boxes, 10x10x8 Inches Tall Cake Box with Window, White Bakery Boxes, Large Baking Boxes, Square Cardboard Cake Box for Multi-Layer Cakes, Cake Decorating Supplies for Gift Giving