I'm about an hour too far north to consider attending a Columbus area show, but I try to hit up as many NE Ohio gun shows as my schedule allows. They are hit or miss. Usually awful deals on garbage, but if you know what you are looking for, how to determine condition, and know what it is worth, then you can find a reasonable deal every so often.
Quite honestly I find the best deals on guns via classifieds websites such as armslist.com or for sale sections in online forums like this one. Again, if you know what something is worth, are able to communicate over email, and are willing to negotiate a little bit you can find much better deals.