Go to the grocery store. Marsh or Meijer if they're in your areas. Go to the "seasonal foods" section. Get the cheapest boxes you can find of plain matzah. Because of Rabbinical restrictions on matzah preparations, most people don't make their own. From the sound of it, you don't need to worry about those restrictions so any non-leavened flat bread would be close enough. I'd stick with the simpliest. It is supposed to be the bread "of affliction" after all, think "what would an Egyptian slave have to bake with?" and go from there.