Google Express is a home delivery service. You can shop at various places and they will deliver it straight to your doorstep or office. Google Express is not available everywhere yet.
The best way to see if you are covered is by opening this site in a private window (or log out from your google account)
If Google Express is available in your area, sign into your Google Account and go here:
Scroll down and you will see a field “Add Membership Promo Code”. Type “SIXFREE” and press redeem. This will give you a six-month free trial time of Google Express which is usually 3 months.
Now it should look like this.
If you are already using the service and are paying for it. You could cancel it and try to signup again with the promo code. Be careful if you have a yearly subscription. Most likely you will void the rest of the remaining days on your yearly subscription.
Have you ever used Google Express?