Marketplace
Add promo code at the checkout, when you buy a $50 Doordash card to receive your discount.
Code can only be used once and expires 5pm (AEDT), 5th April 2021
Limited to one eligible purchase per person, per transaction
I've successfully applied promo code without login, so it's probably not a targeted offer i guess.
Edit: Promo codes appear to be unique.
See also: 10% off Active / 10% off DoorDash / 10% off Cinema Gift cards via Paypal
10% on shopback all day everyday