Decktracker is the best tool any Magic: the Gathering player can have. With advance search filter options, you can search the more than 25,000 cards in the database.
Manage your decks with the built-in Deck Manager.
Manage your card collections via the Collections Manager (requires In-App Purchase).
Pricing information for cards is available via TCGPlayer.
Note that the database can be searched while offline, but Internet connection may be needed to view card images and pricing information.