AmEx offers: 15% off at Starbucks, up to $5 YMMV

Details
Get 15% back as a statement credit by using your enrolled Card at Starbucks by 7/10/2020. Valid in-store at stand-alone Starbucks locations and for app reloads. Limit of $5 in total statement credits. See terms for exclusions.

https://www.amexoffers.com/

Offer Terms
Enrollment limited. Must first add offer to Card and then use same Card to redeem. Only U.S.-issued American Express® Cards are eligible. Limit 1 enrolled Card per Card Member across all American Express offer channels. Your enrollment of an eligible American Express Card for this offer extends only to that Card. Valid in-store at stand-alone Starbucks locations and for app or online reloads at Starbucks.com. Valid at participating locations in US and US territories only. Excludes Starbucks within the following locations: i) retail stores, department stores, supermarkets, malls, outlet malls, ii) hotels, resorts, casinos, convention centers, cruise ships, theme parks, iii) airport terminals, train/bus stations, highway rest-stops, iv) hospitals, military bases, office buildings, and university/college campuses. Excludes delivery orders, Teavana Brand, Princi Bakery, e-gift card purchases, and all gift cards purchased online. Offer is non-transferable. Limit of $5 in total statement credits per Card Member. The enrolled Card account must not be cancelled or past due to receive statement credits. Any benefit earned from this offer is in addition to the rewards (i.e. Membership Rewards or cash back) earned as part of your existing Card benefits, but your ability to earn spend-based rewards for the purchase will be based on the amount after any statement credit or other discount is applied. Statement credit will appear on your billing statement within 90 days after 7/10/2020, provided that American Express receives information from the merchant about your qualifying purchase. Note that American Express may not receive information about your qualifying purchase from merchant until all items from your qualifying purchase have been provided/shipped by merchant. Statement credit may be reversed if qualifying purchase is returned/cancelled. If American Express does not receive information that identifies your transaction as qualifying for the offer, you will not receive the statement credit. For example, your transaction will not qualify if it is not made directly with the merchant. In addition, in most cases, you may not receive the statement credit if your transaction is made with an electronic wallet or through a third party or if the merchant uses a mobile or wireless card reader to process it. By adding an offer to a Card, you agree that American Express may send you communications about the offer. POID: K0U2:0001

I did a search for "starbucks american express," most recent thread that came up expired 4/30/2020.