We haven't cloth diapered very long and our stash is small and simple on purpose because I'm determined to save money with this. Not counting the sewing machine fiasco, I've done pretty well.
I've spent $111.
$36 for a few things from FSOT (For Sale or Trade at DiaperSwappers.com)
$10 for materials to make diapers (two flannel sheets from Goodwill and a few really big men's t-shirts from yard sales)
$10 for sewing notions (scissors, thread, pins, measuring tape, etc.)
$35 for used sewing machine at Goodwill
$20 for a new bobbin case for the machine
And a lot of my time, which is priceless!
I got most of my materials for free from my mom and she has a lot more for me to make some more diapers if I want.
I have made sure that all of the materials I've used are being recycled with nothing bought new for this project. Of the few things that I've bought from Diaper Swappers, they were all mama-made and had a life before coming to live with us.
We have enough for 3-3.5 days right now but I wash every two days because I can't stand dirty things laying around even if they are well contained in my presoak buckets (also recycled, they are one-gallon ice cream buckets). He still wears disposable diapers at night and sometimes on the weekends when his dad changes him.
These will last him through the next few months. At 18 months, he's got at least six more months in diapers, but being that he's a boy (they are hard to potty train) he may be in diapers longer.
If we'd started this earlier we could have saved more money but you can't think of everything.