Peterkin and Walker published in 1976 a cost estimate of feeding a baby in the U.S. At that time, they found there was little difference in cost between breast-feeding and formula feeding. Since then, however, the cost of formula has risen drastically--more than 150% during the 1980s. One researcher estimated that food and feeding equipment cost $855 in the first year. Whereas the cost of formula is quite apparent when a family buys it, the cost of breast-feeding is hidden.