Prefold diapers are the easiest and most economical choice for most cloth diapering parents. They are essentially rectangular pieces of cotton (or hemp) that are sewn together for maximum absorbency. There are typically more layers in the middle and fewer on the sides. You fold the diaper (there are various methods of folding) and lay inside a waterproof cover (such as Thirsties Duo Wrap or Tiny Tush Diaper Cover) and put on baby. These diapers are sewn at the fold lines for easy folding.