Collectible card games were the original free-to-play experience. Having to buy booster packs of cards (micro-transactions, if you will) to improve your deck offered the thrill of gambling with none of the financial reward.
All of which makes Ludosity's Card City Nights a little odd, as it's single player CCG which offers no IAPs.
Buying the game will get you access to all of its 180 cards, which can be earned by playing through the eight-hour campaign.
Card City Nights also adds positional play and combos to the CCG formula. Playing out on a 3x3 grid, the game is all about positioning cards in relation to others to activate powers. Once cards are fused, it is up to you to decide whether to use that power to defend yourself, or attack your opponent.
The entirety of Card City Nights is currently available for half price on the App Store (that's 69p / 99c). So, if you fancy trying out an interesting CCG without the temptation of IAPs you should pick it up now.