If deals were Pokémons, this one’s a shiny: $29.59 (coupon boosted). ET580 2.04 inch AMOLED HD Screen Blood Composition Measurement ECG Electrocardiogram bluetooth Call Heart Rate Blood Pressure SpO2 Monitor ECG Syphilis Function Non-invasive Blood Glucose Multi-sport Modes Music Playback IP68 Waterproof Smart Watch – Black.
Updated:
Banggood
Warehouse in China.
Link: ET580 2.04 inch AMOLED Smart Watch
Regular price: $79.99
$29.59 with coupon: BGET580M
Additional Banggood coupons:
1. First page
2. Second page
Aliexpress
I could not find it on Aliexpress. Click here to search by yourself.
Here are coupons that you can use.
Price history and price alert
Here is price history (for all/most countries) for ET580 2.04 inch AMOLED Smart Watch. The lowest price was: $29.59.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood and Aliexpress (only if product name will be the same as on Banggood and I will post it on social media though, so it’s more like Banggood price alert)).