My mortgage, unsecured credit and I are have had the disadvantage of discovering computer shows.
You can't beat computer shows for chatchkis like odd cables, connectors, adapters and the like (in my experience). If you attend regularly, the vendors will get to recognize and become familiar with you. That can be a good thing, especially with legitimate vendors (most all I have encountered at Cogan, KGP and MarketPro shows are). I started getting a few add'l pennies/dollars/kruggerands off here and there because of my ugly mug! And my mother thought I'd never amount to anything! Go figure!!
I made an impromptu business relationship with one vendor who allowed me to abscond with cases, memory and other accoutrements at his HOME (where he stored his inventory) almost at will for the same or similar pricing. I spent HUNDREDS more with this vendor just in convenience alone and we were both happy campers. So, despite an ugly countenance, I guess I have a trustworthy face as well.
Another large vendor and I became friendly as well. A suave-looking, young Asian whom I used to call "Chĕpay Tyoo" ("pimp" in Mandarin). He got a kick out of a bikerish looking Italian guy's rough Chinese but he cut me some amazing deals on Maxtor hard disks (I eventually bought about 12 in total, 60-120GB). Yeah, they're OEM but he was a good dude and his retail business was about 5 miles from my abode. He also allowed me to buy at about show prices at his store.
Occasionally,you'll find resellers who move previously-owned and -leased products for great deals. From one vendor I bought an Agfa Duoscan scanner - any day of the week, they sell for $250 on ebay - for $25. It included the transparency stage which is a RARE item in its own right. Because I had bought several other items from him (including 7 - 17" monitors for $150 that were nothing short of exquisite) he told me he'd GUARANTEE that it worked properly AND would REFUND my money AND pay my entrance fee to return it next time they were in town. I also scored 8 - 30' BRAND NEW Raritan KVM cables (which sell for $150 each) for $80. Still in the packaging WITH adapters and Raritan part numbers. That's NEW to me.
The proviso was that I SPENT DOLLARS WITH THESE PEOPLE (OK, OK, my name is Lorenzo and I'm a compulsive shopper.). They're in business to move product; if you're looking to snooker a vendor for a PS/2 keyboard adapter just because he recognizes your BBQ sauce-stained Hamfest T-shirt, you're barking up the wrong spanning tree.
There are shlockmeisters there, too, but you have to have a little common sense and intuition. As was mentioned prior, look for vendors who also have storefronts and/or local addresses. You might pay a couple percent more if you buy from them but it's well worth the investment.
It's a good rainy day out, too. Just don't let the little ones eat spaghetti for a month because you dropped a nice bundle at a show.
P.S. The other advice you got here was sound also, so consider my post to be an adjunct.