I just can't imagine there won't be plenty of tickets available on Saturday. The crowd this past week was very thin, but with three home night games in a row to start the season, I suspect some people took the middle game off and will return this week. Plus it's an SEC game and not Arkansas State. I think $90 sounds high, but that may be the market right now. It also depends on how picky you are about where you want to sit. I suspect most State fans are going to have tickets in sections 33-36 or 112-114.
As for parking, yes, there are churches who allow you to park but I don't know their prices. Auburn United Methodist is very convenient to downtown Auburn and easy walk to the game. So is First Baptist Auburn. You could probably call them and get information. The Auburn Church of Christ is on South College but has some parking that is basically adjacent to campus. Fairly easy walk from there to the game, but quite a hike to downtown or any kind of restaurant/bar. You can also try some of the streets just off campus and fall in line there where you see others parking. Pay very, very close attention to most businesses and apartments. You will get towed from there if you don't have permission/pass to park there. My suggestion is to consider the Tiger Transit. That's Auburn's bus system used for the students during school, but on gamedays they transport thousands of people as well. There are several meeting locations around town, each serviced by multiple buses. The buses drop off near the northwest end of the stadium, no more than a quarter mile. The only real downside to the bus is it gets very crowded after the game and you might be waiting in line for a long time. However, if you anticipate leaving early you will have no problems, or if you anticipate hanging around campus or downtown after the game for a while you will have no problem. You will want to choose your bus location based off where you are coming from and which way you are going after the game. You don't want to have to try to cross through game traffic either before the game or especially after. If you are coming from Montgomery on 85, I would try the Auburn Softball Complex or Facilities stops. If you are coming from Atlanta on 85, I would use TigerTown or Duck Samford. If you are coming down 280, I would use the Village Mall.
http://www.auburn.edu/administration/parking_transit/transit/gameday.php
If you want to navigate it yourself, here's the 2013 gameday parking map: http://www.auburntigers.com/gameday/parkingandtraffic.html
Food choices are pretty good, but again, dependent on time, location, when you want to get to campus, what you want to eat, etc. A few local favorites close to campus are
Amsterdam Cafe:
http://www.amsterdamcafeauburn.com/
Price's BBQ House:
http://www.barbecuehouse.com/
Hamilton's:
http://www.hamiltonsonmagnolia.com/
Bloodhounds:
http://thehound-auburn.com/ (I haven't been here but I have heard good things, and that the chef has a tattoo of bacon on his arm and tries to incorporate bacon into everything.)
Zazu:
http://zazuauburn.com/
Big Blue Bagel:
http://www.bigbluebagelanddeli.com/
Bizilia's (if you are letting your wife pick because you dragged her to Auburn):
http://www.biziliacafe.com/
Other downtown choices include Mellow Mushroom, Little Italy (cheap pizza/beer), Cheeburger Cheeburger, Five Guys, Moe's Southwest, Moe's Barbeque, Zoe's Kitchen, and Jimmy John's. West on Magnolia you have other exotic options like McDonald's, Chick Fil A, Subway, Domino's, and Chipotle. At the intersection of Magnolia and Donahue there's also the locally famous original Momma Goldberg's Deli. There is another location on Thach Avenue, a block and a half off of campus (
http://mommagoldbergsdeli.com/).
Hope this helps. Happy to provide as much assistance as I can to anyone who has questions.