Then they would be giving uninformed advice. Like I stated in my first post in this thread, no one can tell you what you should start with. In fact, we're all giving a bit of uninformed advice. The op never stated what he wanted a gun for. If he wants to punch holes in paper then a 9 is good. Hell, save money on ammo and look into a nice .22. That's about the cheapest ammo you can get. If he wants a gun for nearly any other reason then 9mm is not the way to go. Also, like I said in my first post, that's my opinion. I consider it to be a pretty well informed one.
You can get very good deals at shows, but you can also get really screwed. It sounds like the op isn't very knowledgeable about guns. Try to take someone with you who is. If you want to buy from a show then I would still go rent a few first so you know what you like when you get there. How a gun feels in your hand "dry" is very different then when its loaded. The last thing you want to do is buy something that you're not happy with. If you start with the right gun you'll probably end up hooked on shooting. Kinda like reefing!