There were 4-5 guys on the northwest end of the building, right by the main crosswalk from the new parking garage. We didn't talk to them so I'm not sure what their prices were. I'd imagine they're a few hundred for upper deck, which wouldn't matter for this show - the way it's done, there really are no bad seats. There are two stages, and she plays to all areas of the crowd.
I didn't see anyone being turned away for counterfeit tickets, and the guy at our gate said they hadn't had a problem with it so far.
If you strike out and have to use a ticket service, I'd recommend Best Tickets. I've used them for every big event I've attended over the years, including multiple Super Bowls, and they're solid. They still have a few sets for tonight's show in their inventory. You can pick them up at their Research location, or they can email them to you. (I don't work for them, I've just gone through them for tickets since 2009.)
Honestly, I'd just find the cheapest pair you can get no matter where they're located. I shot for good seats, but looking back, it wouldn't have mattered. I hope you find something. Good luck!