I assume they have Wi-Fi at the Expo site? That means they have an "access point" set up, and it basically broadcasts a signal that computers can pick up and use to connect to the Web. If that's there, then all you need to do is install a wireless network card, then when you power up your computer, it will automatically pick up the signal, and ask you if you want to connect. Just tell it "yes" and you're on the Web. For the $50 you're offering to pay to use the setup, you could own a new network card. CompUSA or whatever computer store you go to should be able to hook you up. I like Computer Outlet, myself. I don't own one, so I can't recommend a brand, but there shouldn't be much difference between them; either they work or they don't. If I were in the market, I'd probably buy the cheapest one I could find.

As I've mentioned before, I make my living working on computer networks. If I can help out in any way, feel free to email me, and if you want I'll give you my number. As much as I've gained from this site, I'd be happy go give back if I can.