Prefold diapers are one of the the most economical ways to cloth diaper. They are a rectangular flat piece of fabric that is either folded in thirds and placed inside a waterproof cover (called “trifolding”) or secured on the baby by using diaper pins or a Snappi diaper fastener before putting on the waterproof cover. Using pins or a Snappi will help contain the baby’s poop inside the prefold better then trifolding. Flat diapers are another inexpensive diapering option. These "old school" diapers just just one layer of fabric sewn into a square. They can be folded down several ways to be secured around the baby with pins or a Snappi, similar to how a prefold prefold would be used, or be folded into a rectangle and laid in a cover (called "pad-folding"). All prefolds and flats need a separate waterproof cover to go over it. We recommend buying one cover for every 4 prefolds or flats in your diaper stash. This means that if you are using all prefolds/flats, you will need a total of 24 diapers and about 6 covers (more for a newborn, less for an older baby).