I am f2p and have 2 electro , 2 phoenix (and I will bring the the third xD ) , 2 sonic bird , 2 sphere koriboh ... The real problem for any f2p player is if he does not spend gems very wisely and carefully so many gems are wasted on nothing so baby pay money ... I plan to be P2w player gradually
Play for long enough and earn what you need, then don't waste gems on poor choices. Only purchase packs toward the deck you're working on and stick to making a deck at a time.