It's very similiar free to play affair in which you have hearts that you use to play levels & if you fail you lose a heart. You can pay to refill this meter or like I do just come back later to try the level again.
I've played quite a bit and have just signed for my beloved Liverpool :)
The game does get tough because it has you scoring three or four goals before you can advance to the next stage & the frustration comes in that if you fail one you have to start back at the beginning.
You can use the in-game notes to rewind your attempt to try again, you can get free notes by watching ads or use the in-app purchase model to pay.
