I've been playing it entirely f2p since it was released and don't have any plans to spend money on it, and so far it's been fun enough. Obviously it can be a bit grindy at times, and the gambling makes it such that you'll really need to dump a lot of money into it if you want to get what you want immediately, but it's not that bad as far a f2p games go. It's one of those games where you only really need to play for an hour or two each day in order to progress. That's how I've been playing it for the most part, and I already have a handful of characters who are at max level or are close to being max level. The good rewards from the gambling can still be accumulated over time for free, just at a much slower rate. It can be somewhat annoying at times, but it's far from being pay to win.