Bucket potatoes are awesome however I found out that not all potatoes produce a lot that way. Last year I had yukon golds and fingerlings. I use boxes and the fingerlings grew the entire 4ft deep box but the Yukon's only grew in the bottom layer.
My boxes are built from fence pickets with 2x2's to nest each level together. As the plant grows, I add additional layers and more dirt.
Start small
http://img.tapatalk.com/d/14/04/10/uqarehas.jpg
Then add layers
http://img.tapatalk.com/d/14/04/10/y3abydyz.jpg
http://img.tapatalk.com/d/14/04/10/a6uvu3ys.jpg
Partial harvest.
http://img.tapatalk.com/d/14/04/10/byvubunu.jpg