I have some old t-shirts tucked away in one of my sewing drawers, just waiting to become something else one day in life. These have an inner and snap-in liner made of fluffy Bamboo Fleece. A snap plier set easily makes these adjustable, but you could use a snappi or sew on Velcro, which the babes LOOOOOVE to rip off.
There are lots of free patterns for cloth diapers on the internet. If you have a sewing machine, VERY basic sewing skills, and some absorbent fabric, you can make your own stash of diapers for so much less than buying them. You can customize your child's fit, use your own fabrics and feel so warm and hippy-like. Then your kid shits in them, and the thrill is kinda gone. At least they look cute from behind!