Buy a cheap one and shoot them in the face while they are distracted. (Just Kidding)
I used to be into trick rodeo whipping.
When you are starting out, wear safety glasses.
When I was first starting out, I almost put my eye out.
It's just a good idea. You are going to hit yourself, that is granted, but if you are wearing safety glasses, odds are you will live to tell about it.
If you are going to get serious about it, buy a custom kangaroo leather American style bullwhip.
It will last you a lifetime if it is crafted by skilled hands.
Otherwise, just spend 40-50 bucks on a cow-leather store bought one.
It will probably wear out after a few years of solid use, but it's not worth the 250-500 bucks if you are not going to be serious about it.