I cannot claim credit on this idea. I found it on a blog years ago. I would credit whoever I got it from but it is lost in the mists of time.
So this is the way to make a textured base like say cobblestones or Wood Decking for your figures without having to sculpt each one of them or buy premade bases. It's a little more work upfront, but down the road it pays off.
1. Find a texture you'd like. In my case I used a cobblestone piece my friend Lou sculpted for me.
2. Get some Modeling clay. I used an oven drying clay.
3 Using the clay, make your stamping tool with a small handle. Press it onto the surface of your chosen texture. Then Bake as directed.
4 Once your stamper is done, you are ready to stamp textures onto bases. The original post I got this from used a Plumbers Putty, so I did as well. I imagine you can use Green Stuff or any other 2 part epoxy putty. So using your putty of choice, put a layer onto your base. Then stamp the base. You might want to wet it so it doesn't stick to the stamper.
5 Trim off any excess putty. Let it dry and your done. Depending on your putty you might want to cut it off before it drys or after. You can crank out a lot of bases this way.