As of today, Walmart is now active on Google Express. Very large item selection to choose from, as well as reasonable pricing compared to the pricing inflation of Costco as many members have witnessed when they got rid of memberships.
However, no email has been received about the 20% off Walmart orders and it is not automatically applied to checkout.
After chatting with a customer service supervisor, I was informed that we will need to wait a few more days for marketing to email out the 20% off codes.