This is Amazon Alexa exclusive:-
say "Alexa, buy chicken from Fresh" and it will give you 90 day trail for amazon fresh with no auto-renewal.
Also Use promo code 25FRESH for $25 off your first Fresh order after spending $100 or more.
I got the below email after using the magic word and adding FREE tial to my account:-
Starting today, we have unlocked a free 90-day AmazonFresh trial just for you. As a Prime member, you can now order thousands of items – from apples to deli salads – for delivery to your door.