I have just checked coupons. The lowest price I could get is $31.99 for 1.5L Hydrogen Water Bottle H2 Rich (in Banggood). Basically copy coupon, view price history or create e-mail price alert. What is best price?
Latest coupon and price update (UTC):
1.5L 2 In 1 Portable Hydrogen Water Bottle H2 Rich Water Kettle Sport Hydrogen Water Bottle With Spe Pem Hydrogen Oxygen Separation Technology – Black
Banggood ($31.99)
Banggood warehouse is located in China. As you can see I didn’t find any active coupon for this product right now… Price? Hmmm, price is higher than average (which is $30.99 right now), so better set price alert down below…
Link: Banggood product page
Price: $31.99
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k and https://couponsfromchina.com/short/5cd
Old coupons (from the oldest to the newest): BG157c94
(system checks these coupons on every price check (like once per 24 hours), but you can check them out anyway)
Aliexpress
There’re some similar (or not) items 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 1.5L Hydrogen Water Bottle H2 Rich.
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)).