Your biggest expenditure would be, surprisingly, on diapers and nappies. A newborn baby can go through up to 10 diapers a day, depending on the intake. Dozens of diaper boxes should be ready at home unless you want to make several trips to the supermarket. Some parents opt for a more environment-friendly reusable diaper that you can wash and use repeatedly. Nevertheless, diapers and/or nappies, and wet wipes should be ready at home when the baby comes.