The basics of this deal for Amazon Prime members are pretty simple. Amazon normally sells their Dash Buttons for $4.99, but they're currently offering them for $0.99 AND you get a $4.99 Amazon credit after your first purchase towards with promo code DASHBDAY! So basically you get the button plus $4 to go towards something you know you'll need later on, from toilet paper to coffee to countless other hundreds other everyday household items.
You can purchase up to 3 dash buttons with this promo, but the deal expires on April 5, 2017.
If you're unfamiliar, Amazon Dash buttons are little wi-fi devices that are meant to go around your home. They're meant to make it easier for you to reorder your usual items by the push of a single button. I signed up for a paper towel Dash button and plan on sticking it inside my kitchen cabinet where I store my extra towels. Now comes the fun part of seeing if I can manage to literally push a single button before I run out. Vegas has me as a 2-to-1 underdog!
Note in order to receive your free $4.99 credit, you must use the Dash button once before the end of this year.