There won't be many regular fans at all selling them. You'll see a few scalpers around but they'll be asking absurd prices. Not to mention for a big game like Alabama-LSU (I assume that's the one you're asking about) you'll have to be careful of fakes. I'd advise avoiding trying to find them on gameday, they'll be hard to come by and you'll overpay if you do come across some.
I've never had a problem finding them when I needed to. Just use common sense and don't buy from someone shady. I usually walk around near the stadium about 30-45 minutes before kickoff and find them. As the day goes on, the prices drop. If you're patient and in the right place at the right time, you could find some for face. But I also have the mindset that I'm fine NOT going to the game. Plenty of places around the stadium to watch it on TV.
FWIW, prices have been dropping on StubHub all week. They were starting at $175 on Monday and they're down to starting at $125.