Found another game I -really- like.
Decromancer -- rpg / tactical card game
Freemium, but easily playable w/ no money [more on this later]
Gameplay -- world map, quests, side quests... you level up not only yourself [more points for using cards, etc] but can level up each card to an 'elite' version. Story is actually pretty well written. Injured cards stay injured between battles, but a simple return to a camp will heal all.
Combat mechanics --
You and your enemy each have a front and back row, 5 cards long. You place up to 3 cards per turn. You have access to your entire collection each turn -- no shuffling, etc. Early cards are fairly simple -- melee, archers, healers, etc. but as the game progresses you'll get lots of really cool cards with tons of possible effects.
What can you 'pay' for?
3 things, really, and neither are remotely necessary. The 'premium' currency are asteroids, but you can -easily- earn these for free. Early, repeatable side quests can earn you a couple per mission, but by mid game you can rake them in. Since you'll be playing the game, experimenting with cards, and upgrading cards, you'll soon find yourself rich in these.
These asteroids can be spent on three things --
1) Gives you mana to heal all your cards. Never, ever necessary as a simple trip back to camp will do this for free [the trip will take 10 seconds as your unit traverses the world map]. Mana restores over time, so sometimes you can just heal with free mana anyway.
2) An asteroid is worth 10 experience points for your cards. This is next to nothing, battles give way more. No reason whatsoever to use them in this way.
3) Every 5 or 6 hours, you're offered a card [sometimes really good ones not yet available to you in game]. The first couple times you won't be able to afford these, and you can buy the asteroids to do so. But by mid game, you're rich enough that you can buy all of these w/o thinking. for reference, I have like 300k gold and 100 asteroids in my bank, and haven't spent real money -- doing some fun side missions against really hard enemies often reward 20k gold, 3-5 asteroids, and 25+ experience for your troops.
Early on, when you have no elite troops you might struggle a bit to get them all leveled up, but that's fun and challenging. Eventually you'll have them all elite, and just need to level up new cards you find which is easy enough. [early cards need 15 - 90 elite points to level up, later cards can be 200, etc... but I'm earning 35exp per battle so even if i get a new card it's elite after a handful of battles.
Highly recommended. I'm going to buy some asteroids just to support the game, because i really appreciate that they made it so playable w/o spending anything.