1. Some vendors take cc's but most do just cash. Cash is king and will sometimes get you a better deal too.
2. Very tolerated and even encouraged if you know what you're doing.
3. I have a short list of what i'm looking for then i walk around and see who has what then go back and visit the tables that had what i wanted. I also get there really early, like before the show opens and just wait in line for a few minutes.
4. Just keep them in the container you bought them in and keep their temps between (preferably) 70-85ish.
5. No. When i buy them i usually go there first before anything and they write your name on it and keep it in their freezer for you.