Seems to be targeted for US prime members but worked for me (AU Prime member), login using Amazon AU credentials and check your eligibility.
I was able knock out shipping and tax cost for Wyze Cam 3 with this https://imgur.com/a/N7TewcA
Only works with items shipped and sold by Amazon
Terms and Conditions:
Eligible Prime members who make an in-app purchase on the Amazon shopping app for the first time are eligible to get $10 off their next qualifying $20 order made on the Amazon shopping app.
They are also eligible to receive an additional $10 promotional code ($10 off on $20 in-app purchase of qualifying items) for making a purchase in that app for the second time. Qualifying purchases must be completed before 11:59 p.m. (PT) June 22, 2021.
Offer expires at 11:59 p.m. (PT) June 22, 2021.
Customers must receive notice of the offer directly from Amazon through the Amazon website or email to be eligible. Customers who are forwarded this offer from parties other than Amazon are not eligible for this offer.
US customers who are eligible Prime members (excluding Prime members participating in a free trial of Prime subscription) only.
Promotional code applies only to purchases made in the Amazon shopping app.
Promotional code expires at 11:59 p.m. (PT) June 30, 2021.
Promotional codes only applies to orders including at least $20 of products sold by Amazon.com or Amazon.com Services LLC (look for "sold by Amazon.com" or “sold by Amazon.com Services LLC” on the product detail page). Products sold by third-party sellers or other Amazon entities will not qualify for this offer, even if "fulfilled by Amazon.com" or "Prime Eligible".
Offer does not apply to digital content or Amazon Gift Cards.
Offer is non-transferable and may not be resold.
Offer may not be combined with other offers.
Offer limited to one per customer and account. The maximum benefit you may receive from this offer is $20.
Items must be purchased in a single order and shipped at the same speed to a single address.
Shipping charges and taxes may apply to the full value of discounted and free promotional items.
Taxes, shipping and handling, and gift wrap charges do not apply when determining minimum purchase amount.
Offer discount will be allocated proportionally among all promotional items in your order.
If any of the products or content related to this offer are returned, your refund will equal the amount you paid for the product or content, subject to applicable refund policies.
Offer good while supplies last.
Amazon reserves the right to modify or cancel the offer at any time.
If you violate any of these terms, the offer will be invalid.