I wanted to try making a strap for casual wear. As someone mentioned, I looked for a belt but couldn't find any I was happy with, so I tried to think of another source for a leather strap. Dog leash? I found out most of them are nylon nowdays...
I ended up at the local farm supply store and found a reign that looked like the right size. I took off the "lobster claw" fastener that was pretty bulky and replaced it with a couple of buck-and-a-quarter fasteners, cut the strap to length, punched a couple of holes for the buckle and was good to go!
I don't have any leather tools or riveters or anything so it had to be simple, and this was. And I thought it turned out pretty good for a casual strap, and I have enough reign left to make another.