MOBOX's Clash of Moland game is also free. There seasons are 28 days long (next 1 will start in 4-5 days) where you can compete in 5 leaderboards for MBOX and MEC token prizes. Basically, there are 3 rankings where you can get some small prizes without investment. These are small ones. Approx. value $1-3 altogether. This is my 3rd full season, I hope, this time i can get $5+ in prize, so it's going slowly.

There is also a Tower Defense free p2e game on MOBOX and 1-2 more, but I prefer this one, don't have time for the rest.

In case, you would spend money for these, I am not the best person to ask about that, as I haven't spent any, and still not on those levels, that I could tell relevant info.

In Gods Unchained, you can't reach higher than level8 from the 12 levels (usually i stuck in the Twilight Shadow) without buying packs or cards from other card sets. (what you can by playing the game, earn small, and buy cards from that amount)