Whether you plan on breastfeeding for one month or one year, I recommend that you get yourself some Medela 100% Cotton Washable Nursing Pads. Not only will they save you money, but you'll get to feel good that you're doing your part to reduce, reuse, and recycle. Plus, they're comfortable. There are other brands of reusable nursing pads, and I'm sure they're all perfectly fine, but these are the ones I use and these are the ones I like. I recommend getting 4-5 pairs -- what, you think with a new baby you can get away with doing laundry only once a week? Believe me, you'll be doing lots of laundry, so 8-10 nursing pads should be plenty.
Now, sorting through that huge pile of clean laundry is another story. So I recommend that you get one box of disposable nursing pads as backup. For these, I highly recommend the Lansinoh Disposable Nursing Pads. These are the thinnest yet most absorbent nursing pads I've come across. They won't bulk up under your clothes and won't end up dripping with excess milk. They're excellent backup nursing pads.