Amazon offers Prime Members: select Amazon Dash Buttons for $0.99 each.You will also receive a $4.99 Dash Promo Credit after your first press on the device. Shipping is free. Thanks johnny_miller & lenzbd
Note, you may need to scroll down the page to see the sale prices from the link above.
Example Dash Buttons:
Amazon Gift Card Dash Button $0.99
Charmin Dash Button $0.99
Lysol Dash Button $0.99
Tide Dash Button $0.99
Bounty Dash Button $0.99
Brawny Dash Button $0.99
Finish Dishwasher Detergent Dash Button $0.99
Hefty Dash Button $0.99
Downy Dash Button $0.99
Clorox Dash Button $0.99
Cascade Dash Button $0.99
Trident Dash Button $0.99
Mentos Dash Button $0.99
Clif Bar Dash Button $0.99
Gatorade Dash Button $0.99
Smartwater Dash Button $0.99
Seventh Generation Dash Button $0.99
Dial Dash Button $0.99
Glade Dash Button $0.99
Cheez-It Dash Button $0.99
Red Bull Dash Button $0.99
Pop-Tarts Dash Button $0.99
Izze Dash Button $0.99
Mrs. Meyers Dash Button $0.99
Brita Dash Button $0.99
Ziploc Bags Dash Button $0.99
Milk-Bone Dash Button $0.99
Meow Mix Dash Button $0.99
Greenies Dog Treats Dash Button
Wonderful Pistachios Dash Button $0.99
Optimum Nutrition Whey Protein Dash Button $0.99
Ziploc Bags Dash Button $0.99
Energizer Dash Button $0.99
Amazon Elements Baby Wipes Dash Button $0.99
Aquaphor Baby Dash Button $0.99
Burt's Bees Dash Button $0.99
NERF Dash Button $0.99
Many More
https://www.amazon.com/Dash-Buttons/b?tag=slickdeals09-20&ascsubtag=00fd3368644b11e79dd7ced5612574d30INT&ie=UTF8&sdsrc=staff&node=10667898011
Source: https://slickdeals.net/f/10328856-prime-members-amazon-dash-button-4-99-credit-w-first-press-0-99-free-shipping-today-only?sdxt01=2017-07-08+15%3A35%3A07&sdxt06=Auto+DA+NewReg+Curated+Test+v2%3A%3A%3ATest%3A%3A%3Ada_newreg_curated_v2&sdxt07=119572&p=102011104&utm_source=dealalerts&utm_medium=em-i&utm_term=18&utm_content=11638564&utm_campaign=da_newreg_curated_v2&src=da_newreg_curated_v2_35517904
Interesting thoughts
I don't know enough about all this, its way over my head lol :)