Game Day is free, dunno if that's always the case.
Looks like they are trying to steer people to alternatives today.
Will SEC games themselves be on the app? Bet they make a couple available, at least the ABC ones (and ABC is gone from my YTTV too).
The app very prominently said Game Day was free and it was on ESPN web site too. I think the ABC games are normally watchable on the web w/o a subscription/provider too, but I could be wrong (since I'm usually logged in with one).