I've been playing this game for a month, spent about $600 on it. I am now competing in Silver 2 but my rating is almost Gold rank. You don't need to spend that much money, you can also rent. There are many useful cards that are below $100, especially right now. Also, I don't meet Yodin/Llama/Kron cards that often, people build really powerful decks with other cards. Use your head!