I periodically buy a table at our local gun shows. When I first started, I was only doing training, and my primary goal was to sign up students. You have to consider that it is not only a time commitment, but you also have to pay for the table at the show. I don't know what they charge where you are, but around here they are $65-75 per table.
You should have business cards and maybe build some tri-fold flyers that you can hand out to people that tell all about your group. I found that it worked well for me to get one of those big display boards like kids use at the science fair to build some sort of pictorial story about your business. A bowl of candy will bring people to your table, but that is usually just to show you are a "nice gal" it probably won't get you any more business. if you can have something unusual at your table that gets people's attention and start conversations, that is always a plus. Before pink guns were so popular, I had pink furniture on my AR, and I always had it on my table. People either loved it or hated it, but either way, it got them talking to me.
If you want to spend money on promo items, the sky is the limit for goodies to hand out, but I would keep it simple if you are on a budget or just getting started. Another thing that works to get names and phone numbers for potential members/students is to have a drawing for free training or membership at your club. You will get a LOT of people filling out contact cards that you can use to call and recruit them, but you do have to give a prize to someone.
Just a couple ideas, I hope it helps.