It depends......Are you SOLO? If so then I wouldn't think you would need as much cash as a family of 4. I would seriously consider all of the things you (and the family) might realistically need for (lets say) 5 days. Then figure out how much it might cost you. I'd consider having that on hand. Yes it gets to be a lot. Remember though....money (CASH) talks. Coworkers that went to Mississippi for relief saw this repeatedly. If you have cash and the 'other guy' doesn't....two guesses who will get the stuff (first guess doesn't count).

As for hoarding.....again it depends. I watched a guy with a huge pickup truck with 10- 5 gallon gas cans load up on the stuff and he gave someone the excuse (and it was delivered in a sheepish tone) that he has a lawn service and that he would be, "Needing it anyway." I would consider THAT hoarding. The reason (but more the way he gave it) just appeared to be "manufactured" the moment he was asked. It didn't appear that he really needed it. If you have a reason that a reasonably prudent individual would agree with, than I think it would be more along the way of preparation rather than hoarding.

Just my thoughts