I don't have a hard number to give you, but I do have a couple of things to consider:
In our experience, name brand baby wipes are way too soft to clean dirty bottoms effectively. Babies R Us's store brand (Especially for Baby) is our fave, and they come by the case. Budget for waaay more wipes than you think you'll need. They are useful for so much more than diaper changes.
I nursed for 17 months, and remember: breastfeeding is not free. You need to factor in a pump, storage bags, and bottles. Though the only continuing expense is storage bags. You will be about desperate to get away from baby from time to time, and your spouse and others will cherish the opportunity to feed baby. You can probably rent a pump from the hospital, but depending on how long you want to nurse, it may be cheaper in the long run to buy - check consignment stores. A used pump won't have a warranty, and you will have to by the nipple shields and replacement tubing (for sterility), but it may be cheaper to do this than to buy the whole set brand-new. Also, instead of using breast pads for leaks, you can cut panty liners to fit into your bra, depending again on what deals/coupons you can find where. Leaking will not last more than a few months for most moms - your breasts will adjust to baby's schedule, once baby has one. However, DO NOT skimp on lanolin cream. You will be much more comfortable - just go ahead and buy the Lasinoh; it does cost more, but it works better than the Gerber. I promise - been there, ouch.
Consumables to factor in: baby Tylenol, baby soap (though you'll use less of this than you imagine), baby toothpaste as well as a toothbrush (you need to start brushing as soon as baby starts cutting teeth), diaper rash cream (something you'll hopefully also use less of than you think), Orajel or the teething comforter of your choice, the gentle detergent of your choice (when we had our baby, Dreft was cheaper by the load than Woolite; I used it for my delicate washing as well as for baby's things - you will use MORE of this than you imagine), stain remover. Some folks also use gas tabs, saline drops, and ear drops, but we used them rarely, if ever.
BATTERIES. We were amazed at how many infant things required batteries; the swing, the baby monitor, and the play mat were the big ones. Not to mention the camera. Invest in a battery charger and good rechargeable batteries. More expensive at first, but you will be replacing batteries a lot as baby grows (and as toys become more sophisticated).
And, of course, things get lost. Socks, teething rings, that sort of thing.
BTW, how's your long-distance calling plan?
Best wishes!