If I am going from Pudong Airport to Dashijie, which transportation card should I get ?

The Maglev Round Trip + Metro One-day Pass costs CNY 85 and allows passengers to take a maglev round-trip (economy class) and unlimited metro rides within 24 hours after the first use. The validity period of the return Maglev is one year. The Ordinary Return Ticket (valid in 7 days) costs CNY 80.
According to your situation, you are advised to purchase Maglev Round Trip + Metro One-day Pass and Metro Three-day Travel Pass.
Metro Three-day Travel Pass: The pass is sold CNY45 and could be purchased at any ticket booths set at these metro stations. With this pass, you could take all the metro lines without limit in 72 hours after the first use.