I found we didn't need too many clothes in the 0-3 month range, as babies grow soooo fast during this time. If I were to do laundry once a week, I would say have maybe 14 or 15 sleepers of this size. (You want more than one per day, as there are often poop and vomit accidents). I would also reccommend not buying any other clothes BUT sleepers- t-shirts, jeans, sweaters and hoodies are CUTE, but VERY impractical for babies at this age. I found even onesies with bare arms and legs weren't that great, as babies of this size could get cold a lot faster than you or I. Save the "cutesie" clothes for when the baby is 6 months or older :)

You may also find this question helpful.

http://moms4mom.com/questions/2708/how-many-outfits-does-an-infant-really-need

You very likely will want to swaddle your baby at night. Consider the temperature inside your house at the time of year your baby's due (August?) for what kind of outfits to put him in underneath the swaddler. My guy was born on May 17 so we had some hot months and didn't want to use the A/C constantly, so the indoor temp was around 70-75 (20 to 23 C). We put him in short-sleeved onesies underneath his swaddler.

BTW you may want to invest in a few of the Kiddopotamus SwaddleMe wraps. My kid was quite the squirmer and managed to get out of any attempts at swaddling with a plain blanket. I've heard the same story from lots of other parents.

Another warm-weather tip -- you want to cover his limbs when he goes outside so he doesn't get too much sun, but you don't want him to get hot and sweaty. Very light pants and long-sleeved shirts are a must in that case.

I read somewhere that infants will cry when they're too cold, but not when they're too hot. So it's safer to underdress than overdress.

One more point: don't buy "newborn" sized clothes. If your baby is full-term, the NBs will likely already be too small. If your baby is not full-term, you will probably have a chance to rush out and get some smaller clothes before he/she comes home.