If you've not played Magic in over a decade and want to tap some mana, this may just be the game you want to pick up. Here, you get a number of decks to play with, several modes and styles of play including multiplayer.
Things to keep in mind:
You won't find cards from the early era of magic you may recall from ages past. Alpha, beta, The Dark, Arabian Nights? Unlimited, & 3rd edtion? Not here. What you will find are a selection of decks from moderan 2013 era magic. What matters however is that you are given numerous ways to play the game and a number of various decks to mess around with.
You can buy this with a number of unlocks set, or with all cards unlocked. The locked variant might be for you if you enjoy the challenge of unlocking cards and the related achievement pleasure that can be had from unlocking. If you just want to play with cards, as many as you can get your mits on (without grinding) - you may want the 'Complete' edition.
At worst, in this release you can't build decks from an entirely raw ensemble of cards. You can however heavily modify the numerous decks that you are given. Most of these decks have anywhere from 30 to 40 specific deck limited extra cards that can be added or used to replace default deck setups to modify your style of play. Despite these official limitations of the 2013 M:tG game, there is actually something of a modding scene. Google for mods and you may just stumble into what you want if you really want to build decks from scratch / have minor game play bugs fixed.
A very minor user specific issue that can be disabled: Foil cards. IRL they're entertaining and in the game you can have them too. Yet they're animated and constantly glimmer. The constant animation can become a little irritating, turning a novelty special card into a literal headache. Fortunately, - the game has an option to remove the appearance of foil on all foil cards.
So, all in all this is a solidly entertaining version of Magic to mess around with on a computer. Be it offline multiplayer locally, online multiplayer, or in single player vs. AI's of varying difficulties.