S., in my experience it's varried by product. My daughter (just turned 1) has been on formula since she was a couple of days old, she just didn't take to breastfeeding. Originally I started with name brand Similac Advance, only because that was the sample I got in the mail. Then a friend reccommended I try the store brand, which is nutrient for nutrient the same as Enfamil Lipil, which is the Similac competitor. Formula is FDA regulated so there is a standard set of criteria to make it safe. I bought mine from Sam's club, but the same manufacturer makes the Walmart brand, BJ's, Costco, etc, and my daugter has flourished on it. I've saved tons on that.
I've bought Sam's club or walmart brand baby wipes since she was born and they've worked great.
Diapers, I really do think the pricey ones are nicer, they're thin, absorbant, fit her bum well, but they are SO expensive. I tried the Babies R Us brand of diapers and just loved them for a while, but then my daughter started growing out of the absorbancy quicker, and they were kind of bulky. They're a great price though. I went with the Sam's club, walmart and kmart diapers as well, and I thought they were wayyy to bulky. But they were cheap. Then I found a happy medium- Luv's diapers. They're not as pricey, but made by the makers of Pampers so they are very similar in style. Great absorbancy, pretty thin, and a good price at Walmart, or even better at BJ's.
Clothing- my daughter wears lots from walmart, because she'll just poop and spit up on things so why spend more?
Walmart has great fruit baby food and puffs, comparable to Gerber. Beechnut is the cheaper baby food brand than gerber and has a great variety and larger size in some items.
Baby shampoo- there's always a store brand of Johnson's and Johnsons and it works just the same.
I liked Dr. Brown's bottles- they have a venting system that's supposed to prevent air bubbles in their tummies, but I really don't know how it differs from cheaper simpler bottles that don't have all of those extra pieces to clean.
Anyway that's my two cents, and some may disagree on some things, but the formula thing I feel very confident about! :) Good luck and congrats on your new one!