Never spend any money on this game...They keep a track of who is spending money and they make there team perform bad intensionally so that they can force them to spend extra money..The same way who heals there player by purchasing red packs there players get injured much more than others...
And the biggest one what's the point of making your team stronger when league, cup and champions league are decided on the overall rating of your team...My another account team is level 4 with only a average rating of 21 stars and I even barely open that account even there morals are low inspite of all this they are at the top of the league...