Been playing it for over a year, have all cards up to tournament standard and hovering at about 4k rating. Have spent probably close to 150 dollars on it that i do not regret. It is more fun than wow and less expensive, especially in the long run. Now that i have a solid base of cards i am really not incentivised to spend any more money and probably won't except for the rare 2$ 5x value offers which come up every month or so where as in a game like wow i would have to spend 60 bucks every year on an expansion and another 100 on subscriptions, have to constantly grind so need to invest loads of time.. Ugh

In tournament mode the levels are capped so it is an even playing field where spending money doesn't get you wins. I believe other developers have a lot to learn from their model