Unfortunately I then discovered that Star Trek - Wrath of Gems is one of the more exploitative Free2Play games. Basically the problem is that the enemies become stronger faster than you do if you don't spend money. And you can't very well farm the lower level content either, because after 4 wins a scenario only gives out very minor rewards. You can do PvP or special events, but you can't win anything with a weak starting team there either, the other players are already too advanced. Plus whenever your star ship or characters get hit, you need to wait some real time for them to heal before trying again, if you don't want to start with a disadvantage.

So you need more slots for ships and characters, and those cost coins you mostly get for real money. The same coins also buy you the booster packs in which you find those ships and characters (you can buy very basic boosters for dilithium crystals which you can either buy or get from playing). And you don't need to find those ships and characters just once, but need either several copies to upgrade them or spend coins for the upgrade. An upgrade then raises the level limit, but you still need a lot of dilithium crystals to actually level up.

I got sucked into that and feeling generous towards myself I spent more money on this "free" game than what I would have spent on a full price PC game. I did that consciously, and it enabled me to get to a point where my team was strong enough to win and earn the rewards I need to play on. But I really can't recommend a game like that. Even if you can afford it, it leaves a bad aftertaste of having been exploited.