I have seen a couple websites, such as this one, which strongly advise against putting one's hand into a garbage disposal, in order to clear it out. If the garbage disposal is turned off, is there really much risk in doing so? It seems that some disposals do not even have very sharp blades.
It would be up to you to decide the value of your hand.
I rather enjoy having my hands, so I use a stick when needed. Never felt the need to buy a specialized tool. Sometimes what's jamming the garbage disposal is, itself, sharp - a tin can lid or glass object, for instance. Naturally, those things are not supposed to be in there, but it does not mean they can't be in there, by accident. It's also a fairly nice place for growing things you probably don't want to get in a scratch, much less a full blown cut. So, even if the thing is unplugged or turned off at the circuit breaker, there's a hazard - if it's only turned off at the wall switch, there is always at least some potential for it to be turned on with your hand in there, and that would be rather unpleasant - but some folks don't want to bother making sure it can't be turned on, because they are sure it won't be...
I once put my hand in a garbage disposal to check if I could find the cause of a drain stoppage. After disturbing some food particles, and wanting to see if this action had helped, I was frightfully surprised when I realized that I had subconsciously flipped the switch on before I got my hand out of the disposal. Fortunately I had unplugged the disposal before I did all this.
Ecnerwal may be right about the risk of bacteria. So, you may want to wear gloves. But you definitely want to unplug the disposal before you think about putting your hand in there.