The Cost of Formula Feeding
Barbara Robertson, IBCLC has a very interesting article on the cost of formula feeding: https://bfcaa.com/resources/cost-of-formula-feeding/. While breastfeeding / chestfeeding isn’t necessarily free, the costs are usually much less than exclusive formula feeding.
TL;DR: Total for one year: Between $2730 (using an average cost formula) and $4200 (more expensive formulas).