I am a day 1 player who has never spent a dime of real money on this game. After getting bent over by EA on Madden Mobile, I told myself I'd never spend another dime on a EA product (unless they bring back NCAA FOOTBALL.) The only purchases I've made on this game have been with Google Play credits obtained through Google Opinion Rewards, thus not a penny out of my pocket.
That being said, I would sign up for a 3 to 5 dollar a month subscription if it meant having unlimited energy and unlimited (or up to like 30) hard node attempts.
Other than that, I'll continue being a f2p player. Yeah I don't get special people 1st release. But I still get them. So what I said is the ONLY way I'd sign up for a subscription service to this game.