I got a player injured for 6 days, I let him heal by himself without red packs.
Today I make him play the second half of an easy friendly to get him going and he gets a different unrelated injury. 12 days now.
Let's do the math. Currently 89 "tokens" cost you 9,99 euros.
Now you want red packs and green packs. You need 15 red packs for anything above 4 days.
That means you need a 25-packer. 24 "tokens", in practice 2,70€
He gets a new injury? you need 5 red packs more. That'll cost you 6 "tokens" (0,67€) provided you still have 10.
I'm not even counting the green and blue packs you may need.
This means every situation likes this can cost you around 3,50 €uros.
A simple injury means €1,70 they want from you every two or three games.
Considering that they have increased the injury factor lately (to stop you from harvesting packs), training players may cost you an awful lot of real money if you fall for it. And definitely your hospital won't generate enough red packs if you can't harvest them.
Resist. If you feel mugged, just exit the game. Games in the 90's used to be about fun. You'd pay 80€ for a console cart once, but you'd have happy times for a lifetime.
Above all, it's very sad to think that kids have full access to Facebook these days and that they'll be exposed to this kind of pressure after being attracted by the fancy games, supposed to be free.