In a month I am making a three-tiered cake where the bottom is to be a 12" round cake, but I don't have a round pan that size.
Does anyone have an idea to make a round cake anyway?
I have a square pan that size, but it will take a great deal more ingredients, and I would like to keep the cost down.

I really have no idea other than baking it in a square pan and carving the circle... or maybe if you want, you can have a square bottom tier and 2 rounds on top. Better off getting a 12 inch round pan.

Good luck.