Prefolds + Cover: The Original Cloth Diaper
Prefolds, so called because they've been folded and stitched with more layers in the middle to create a thicker center, are those cloth rectangles you picture when you think of old-school cotton diapers. They come in a variety of other fabrics, including bamboo and hemp, as well as varied sizes. At about $2 and up each, prefolds are the foundation of your least expensive cloth-diapering option. Actually, if you plan to go with a diaper service, they are often your only option. The dirties are whisked away regularly and replaced with a freshly laundered batch.
Whether or not you go with a service, you'll still need to get your own diaper covers -- the waterproof outer layer that contains the inner, absorbent prefold's wetness and mess. The most popular covers mimic the shape of disposables, wrapping around the prefold and closing at a baby's hips with either a series of snaps or Velcro, in place of sticky tabs. They're usually made of a poly-blend fabric with a waterproof laminated interior and come in all sorts of colors and prints. Price per cover starts at about $8, with the average landing at about $12.
My hand-me-down set consisted of prefolds and covers, and I loved that I could often replace the soiled prefold with a fresh one and reuse the cover (after a quick wipe-off, if necessary), thus cutting down on laundry. Fellow parents often asked me about diaper pins; I'm happy to report they're no longer necessary. Some people use separate stretchy one-piece fasteners called Snappis in addition to the snaps or Velcro to make sure prefolds stay in place, but I found wrapping the covers tightly worked just fine. And while I chose to use disposables at bedtime, many parents just double up on prefolds, or add cloth inserts called soakers, to make it through the night without leaks.