Several years ago I was at a do-it-yourself sex toy workshop. It was a hands on thing with lots of stuff the workshop leader had brought, all stuff that could be found, not bought. I watch as everyone, including the workshop leader, make didlos out of rolled up packing material (some so big you'd need a gallon of lube and a pile driver to actually use them), and other folks trying to make strapon harnesses and floggers out of old bicycle inner tubes.
The workshop was at the place that was also a commune/collective that had a kitchen. I asked one of the people that lived there if they had any dry beans in the cupboard, and they did, a back of dried black beans. I took the beans and about a foot of bicycle inner tube (can't believe nobody else thought of this). I tied off one end of the inner tube about an inch from the end with some thin string, filled it with the dry beans to about an inch from the open end, packed them in good, then tied that end off. Finally I folded the ends past the string tie-offs back, stretching that part around the part filled with beans so the string was now covered and the end was a curious pucker.
I slipped a condom on the whole thing and handed it to the workshop leader - whose jaw dropped as she felt the texture and flex of the thing. There was a sex party there that night, and my creation got a lot of use.
I've done variations on that theme since then. A really skinny inner tube and a collection of large beads and smaller beads can make an interesting butt toy. Different fillings, from sand to rice to larger things give different textures. You just need to seal the ends so nothing leaks out.