While your upfront cost is more you save soooo much in the long run! You could gradually add to your diaper stash as you get the funds but you can also create a registry at most diaper sites. I have done very well with pinstripesandpolkasdots.com and greenmountaindiapers.com
If you go with prefolds and covers it is much cheaper than pocket or all in one diapers. I love my pockets and aios better but I am still using the same prefolds I bought when my daughter was 4 months old and she is about to turn 2! Talk about savings! I bought 2 doz prefolds and 5 covers and they have held me for a long, long time! And 2 doz was more than enough. I would wash every other day or so when she was younger. I use the bummis and bluberry covers. But if I had it to do over I would only buy things that will carry me thru more than one size to stretch my dollar farther.
Thirsties also now makes a Duo diaper that will carry baby from birth to 18lbs. Then the size 2 carries baby from 18-40lbs! They also make a cover version of it as well to go with prefolds.
If you buy prefolds definitely spend your money at green mountain diapers. They are the gold standard of prefolds. Like I said mine have held up for almost 2 years! I use them in rotation (so the same diapers arent' getting used over and over-the ones that get washed go to the bottom of the clean pile), I rarely bleach, never use vinegar (acids will break down your diapers faster), don't soak, use a tablespoon of diaper compatible detergent (like Arm & Hammer Free & Clear Essentials), do a cold pre-rinse, hot wash with tablespoon of detergent/rinse, then hot wash/rinse cycle with no detergent.