This was sent to me by a friend so I have not tried it myself but she tells me that it was successful and others she knows have done it as well.
Go here and create an account (has to be a new account no old accounts it will not work).
Once you are logged in to to Get $0 Delivery With DashPass
Opt for the 1 month free trial offer (don’t forget to cancel this before the month is over) Tell Alexa to remind you!
Go back to the main page and look for the banner that says “DEALS ALL SUMMER LONG”
Then click on “learn more”
The “order now”
Add at least $15 worth of food from a participating restaurant in your area.
Proceed to the checkout and select “SUMMER OF DASHPASS”
You will get $15 off your bill + free delivery!
There is a possibility you will get an additional $15 off ($5 off your next three orders) some are getting it using my link above.