A.B.
I chose to bottle feed both of my kids, and it was great. I never had any problems... never heard of formula causing constipation (you hear all kinds of horror myths from anti-formula groups who swear anyone who doesn't breast feed is a demon)! Anyway, the brands are all fine... but you'll need to figure out what type of formula the baby needs (regular, soy, increased iron, etc). It is possible that the ones high in iron would cause constipation b/c of the IRON, not the formula itself. I really found that the wal-mart brand was just as good as Carnation Good Start, Enfamil, etc. We mixed brands sometimes-- enfamil makes these to go packets that we loved!! It was the perfect amount for a bottle.
We kept gallons of purified store-bought water. You just follow the instructions for what amount of formula to mix with what amount of water. We never heated the bottles or anything like that.
The cost is about $15-20 per can, and you need at least 1 can a week... from what I remember.
Bottle feeding allowed my husband to do all of the night feedings as I was recovering from childbirth. My kids never got sick or anything... neighbors did breast and both kids were constantly sick and plenty of allergies, but we never had any problems. I don't believe for one second that breast feeding has much to do with a baby's health... nutrition is nutrition, and at least with formula, you are certain about that nutrition, as with breast milk, it is a gamble.
Good luck.