This app was mentioned in 5 comments, with an average of 1.00 upvote
I spent about $5k on Deck Heroes a few of years ago. Played it for a couple of months, got to #1 in arena and never touched it again....
I'm surprised no one has mentioned Deck Heroes yet. it has IAPs, but I've played form months without paying for anything. plus they give you their pay currency for doing stuff, like logging in, albeit not a lot.