Okay so I am completely new to this. I am making my very first decorated cakes for a friend on the 5th. They will both be bowling themed cakes with a few fondant toppers and I would like to be able to find boxes that will fit them both, but I am having trouble finding any that would be tall enough.

The first is just a simple 6" round smash cake. I'm using an 8" cake board because I plan on doing a thicker border and then setting that on top of a 10" cake board to decorate with wrapping paper and contact paper. I wanted the cake to be at least 8" tall (toppers included)

The second cake (including cake board) will be about 15" x 20" and I want it to be about 10" tall

I've looked at Walmart and Michael's and several places online and no luck. Any advice??

For tall cakes, I have the same problem.  Kara Buntin has a great video on making your own cake boxes.  

Good luck!  

I go to a box store and use this method 

I just go to Walmart and use shipping boxes for my tall cakes