Are you going to work outside the home? The #1 cost will then be daycare and that varies by city (ours is a center $1200/month).
Your healthcare will increase, check with your employer. Compare who has the better plan if you each carry your own. (Our son had many ear infections - $30 co-pay per visit....18 visits the first year + Rx each visit.)
Diapers, it depends upon brand name or store brand - about $20 per week. (cut coupons...we've never purchased them without a coupon!)
Formula, it depends upon brand name or store brand - toward our son's first birthday - 2 cans of Similac per week.
Jarred food was about $3 per day - he only ate it a few months, much preferred our food from the table! We ended up giving most of it to a food pantry.
Clothes, that is all over the place! I LOVE sales and I always "prebuy" coats, boots & jackets at clearances. I also enjoy going to re-sell it shops.
Shoes, if you have odd sized feet - Striderite $40 per pair every 3-4 months.
We registered for the larger items, such as the pack-n-play, stroller & car seats. Our car seats go from 5 - 60lbs.
If you can get some things at re-sell it shops, such as exersausers...extra stroller for the car. Most of the items you use for such a short period of time!
Some things cost a lot less once you have kids
. A trip to the park on a Saturday evening is really cheap! Walking around the block and picking up acorns. Going to the mall and throwing pennies in the mall. The coffee shop for a shared bagel (bread machine sliced) another popular entertainment dollar. You will rent more movies...is it worth getting a sitter to sit in the dark & watch a movie. You will save money by eating dinner at family style restaurants - those with good kids meals that get you in/out quickly! You won't drink too much when you are out either...sleeping in will become a thing of the past!