The World of Warcraft TCG is a great add-in to the popular online game. The $20 listed is only for the starter set, but like all collectible card games it requires a larger collection for the best game experience which requires buying packs at $4 each. It's a little pricy but it's on par with other card games and it's cheaper to buy whole boxes rather than individual packs.
Aside from the packs, the gameplay and art are what people will be more interested in reading about. This game has great illustrations that can serve as an inspiration for your own online characters or as just great fantasy images. No longer limited to the typical "big hands, big armor" syndrome the online game suffers from, the characters portrayed in the game actually look human instead of some little tykes version of humans. The illustration for actions and items are also just as great.
The gameplay is fast and easy. Just like games like chess, the game does not bog down the player with a plethora of advanced rules in order to seem strategically deep. The game is deep because of the inherent gameplay mechanics which are easy to follow. No one game will ever play the same because of the random chance involved and like all great card games, game theory and weighing your risk vs. success is important.