Instacart expanded into the Inland Empire and I received the following via email. I would also note that my first order came with Free Shipping.
Shop from Stater Bros, Costco, Petco, Ralph's, and Smart & Final! Receive $20 in FREE groceries on your first order!* To redeem enter the code HELLOLOSANG
in the "Add Promo Code" section of your Instacart account settings.
*Credit expires 09/12/2017 at 11:59pm PST. Offer valid on first-time orders of $35 or more made through Instacart. Instacart and/or certain retailers, may not be available in all zip codes. See full credit terms here: http://inst.cr/t/uMMW3rKd1
. Other questions? Visit http://www.instacart.com/help