I'm feeling the same way about Minion Masters. I just play it on my Steam Deck, but it got an Android release recently. They gave away a few of their "DLC" packs (which is how I found it about it), so maybe my experience is a bit atypical, but I've just been playing for a week or so and I already have more than half the available cards and enough currency that I can craft any cards I really want to finish a deck.

I haven't paid a cent. It's so generous with its freemium model that I'm probably going to buy an in-game currency pack if I'm still playing once my Google Rewards wallet ticks high enough to buy one.